diff --git a/controller/RestController.php b/controller/RestController.php
index 0e22e6fab..c3a1c2808 100644
--- a/controller/RestController.php
+++ b/controller/RestController.php
@@ -200,6 +200,7 @@ public function vocabularyInformation($request)
                 'skos' => 'http://www.w3.org/2004/02/skos/core#',
                 'onki' => 'http://schema.onki.fi/onki#',
                 'dct' => 'http://purl.org/dc/terms/',
+                'dcterms' =>'http://purl.org/dc/terms/',
                 'uri' => '@id',
                 'type' => '@type',
                 'title' => 'rdfs:label',
@@ -208,6 +209,7 @@ public function vocabularyInformation($request)
                 'defaultLanguage' => 'onki:defaultLanguage',
                 'languages' => 'onki:language',
                 'label' => 'rdfs:label',
+                'subject' => 'dcterms:subject',
                 'prefLabel' => 'skos:prefLabel',
                 'title' => 'dct:title',
                 '@language' => $request->getLang(),
@@ -254,6 +256,7 @@ public function vocabularyStatistics($request)
                 'void' => 'http://rdfs.org/ns/void#',
                 'onki' => 'http://schema.onki.fi/onki#',
                 'uri' => '@id',
+                'dcterms' =>'http://purl.org/dc/terms/',
                 'id' => 'onki:vocabularyIdentifier',
                 'concepts' => 'void:classPartition',
                 'label' => 'rdfs:label',
@@ -549,6 +552,7 @@ private function returnDataResults($results, $format) {
                 'dct' => 'http://purl.org/dc/terms/',
                 'dc11' => 'http://purl.org/dc/elements/1.1/',
                 'uri' => '@id',
+                'dcterms' =>'http://purl.org/dc/terms/',
                 'type' => '@type',
                 'lang' => '@language',
                 'value' => '@value',
@@ -734,6 +738,29 @@ public function hierarchy($request)
         if (empty($results)) {
             return $this->returnError('404', 'Not Found', "Could not find concept <{$request->getUri()}>");
         }
+      
+        // set the "top" key from the "tops" key
+        foreach ($results as $value) {
+            $uri = $value['uri'];
+            if (isset($value['tops'])) {                
+                if ($request->getVocab()->getMainConceptScheme() != null) {
+                    foreach ($results[$uri]['tops'] as $top) {
+                        // if a value in 'tops' matches the main concept scheme, take it
+                        if ($top == $request->getVocab()->getMainConceptScheme()) {
+                            $results[$uri]['top'] = $top;
+                            break;
+                        }
+                    }
+                    // if the main concept scheme was not found, set 'top' to the first 'tops' (sorted alphabetically on the URIs)
+                    if (! isset($results[$uri]['top'])) {
+                        $results[$uri]['top'] = $results[$uri]['tops'][0];
+                    }
+                } else {
+                    // no main concept scheme set on the vocab, take the first value of 'tops' (sorted alphabetically)
+                    $results[$uri]['top'] = $results[$uri]['tops'][0];
+                }
+            }
+        }
 
         if ($request->getVocab()->getConfig()->getShowHierarchy()) {
             $schemes = $request->getVocab()->getConceptSchemes($request->getLang());
@@ -743,12 +770,13 @@ public function hierarchy($request)
                 }
 
             }
-
+            
             /* encode the results in a JSON-LD compatible array */
             $topconcepts = $request->getVocab()->getTopConcepts(array_keys($schemes), $request->getLang());
+           
             foreach ($topconcepts as $top) {
                 if (!isset($results[$top['uri']])) {
-                    $results[$top['uri']] = array('uri' => $top['uri'], 'top' => $top['topConceptOf'], 'prefLabel' => $top['label'], 'hasChildren' => $top['hasChildren']);
+                    $results[$top['uri']] = array('uri' => $top['uri'], 'top'=>$top['topConceptOf'], 'tops'=>array($top['topConceptOf']), 'prefLabel' => $top['label'], 'hasChildren' => $top['hasChildren']);
                     if (isset($top['notation'])) {
                         $results[$top['uri']]['notation'] = $top['notation'];
                     }
diff --git a/model/GlobalConfig.php b/model/GlobalConfig.php
index 4080e94fe..8138a0b5b 100644
--- a/model/GlobalConfig.php
+++ b/model/GlobalConfig.php
@@ -1,243 +1,243 @@
-<?php
-
-/**
- * GlobalConfig provides access to the Skosmos configuration in config.inc.
- */
-class GlobalConfig {
-    private $languages;
-
-    public function __construct($config_name='/../config.inc') 
-    {
-        try {
-            $file_path = dirname(__FILE__) . $config_name;
-            if (!file_exists($file_path)) {
-                throw new Exception('config.inc file is missing, please provide one.');
-            }
-            require_once($file_path);
-            if (isset($LANGUAGES)) {
-                $this->languages = $LANGUAGES;
-            }
-        } catch (Exception $e) {
-            echo "Error: " . $e->getMessage();
-            return;
-        }
-    }
-    
-    private function getConstant($name, $default)
-    {
-        if (defined($name) && constant($name)) {
-            return constant($name);
-        }
-        return $default;
-    }
-
-    /**
-     * Returns the UI languages specified in the configuration or defaults to
-     * only show English
-     * @return array 
-     */
-    public function getLanguages() 
-    {
-        if ($this->languages) {
-            return $this->languages;
-        }
-        return array('en' => 'en_GB.utf8');
-    }
-    
-    /**
-     * Returns the vocabulary configuration file specified the configuration
-     * or vocabularies.ttl if not found.
-     * @return string
-     */
-    public function getVocabularyConfigFile() 
-    {
-        return $this->getConstant('VOCABULARIES_FILE', 'vocabularies.ttl');
-    }
-    
-    /**
-     * Returns the external HTTP request timeout in seconds or the default value
-     * of 5 seconds if not specified in the configuration.
-     * @return integer
-     */
-    public function getHttpTimeout() 
-    {
-        return $this->getConstant('HTTP_TIMEOUT', 5);
-    }
-    
-    /**
-     * Returns the SPARQL HTTP request timeout in seconds or the default value
-     * of 20 seconds if not specified in the configuration.
-     * @return integer
-     */
-    public function getSparqlTimeout() 
-    {
-        return $this->getConstant('SPARQL_TIMEOUT', 20);
-    }
-    
-    /**
-     * Returns the sparql endpoint address defined in the configuration. If
-     * not then defaulting to http://localhost:3030/ds/sparql 
-     * @return string
-     */
-    public function getDefaultEndpoint() 
-    {
-        return $this->getConstant('DEFAULT_ENDPOINT', 'http://localhost:3030/ds/sparql');
-    }
-    
-    /**
-     * @return string
-     */
-    public function getSparqlGraphStore() 
-    {
-        return $this->getConstant('SPARQL_GRAPH_STORE', null);
-    }
-    
-    /**
-     * Returns the maximum number of items to return in transitive queries if defined
-     * in the configuration or the default value of 1000.
-     * @return integer 
-     */
-    public function getDefaultTransitiveLimit() 
-    {
-        return $this->getConstant('DEFAULT_TRANSITIVE_LIMIT', 1000);
-    }
-    
-    /**
-     * Returns the maximum number of items to load at a time if defined
-     * in the configuration or the default value of 20.
-     * @return integer 
-     */
-    public function getSearchResultsSize() 
-    {
-        return $this->getConstant('SEARCH_RESULTS_SIZE', 20);
-    }
-    
-    /**
-     * Returns the configured location for the twig template cache and if not
-     * defined defaults to "/tmp/skosmos-template-cache"
-     * @return string
-     */
-    public function getTemplateCache() 
-    {
-        return $this->getConstant('TEMPLATE_CACHE', '/tmp/skosmos-template-cache');
-    }
-    
-    /**
-     * Returns the defined sparql-query extension eg. "JenaText" or 
-     * if not defined falling back to SPARQL 1.1
-     * @return string
-     */
-    public function getDefaultSparqlDialect() 
-    {
-        return $this->getConstant('DEFAULT_SPARQL_DIALECT', 'Generic');
-    }
-
-    /**
-     * Returns the feedback address defined in the configuration.
-     * @return string
-     */
-    public function getFeedbackAddress() 
-    {
-        return $this->getConstant('FEEDBACK_ADDRESS', null);
-    }
-    
-    /**
-     * Returns true if exception logging has been configured.
-     * @return boolean 
-     */
-    public function getLogCaughtExceptions() 
-    {
-        return $this->getConstant('LOG_CAUGHT_EXCEPTIONS', FALSE);
-    }
-    
-    /**
-     * Returns true if browser console logging has been enabled,
-     * @return boolean
-     */
-    public function getLoggingBrowserConsole()
-    {
-        return $this->getConstant('LOG_BROWSER_CONSOLE', FALSE);
-    }
-
-    /**
-     * Returns the name of a log file if configured, or NULL otherwise.
-     * @return string
-     */
-    public function getLoggingFilename()
-    {
-        return $this->getConstant('LOG_FILE_NAME', null);
-    }
-
-    /**
-     * @return string
-     */
-    public function getServiceName() 
-    {
-        return $this->getConstant('SERVICE_NAME', 'Skosmos');
-    }
-    
-    /**
-     * @return string
-     */
-    public function getServiceTagline() 
-    {
-        return $this->getConstant('SERVICE_TAGLINE', null);
-    }
-    
-    /**
-     * @return string
-     */
-    public function getServiceLogo() 
-    {
-        return $this->getConstant('SERVICE_LOGO', null);
-    }
-    
-    /**
-     * @return string
-     */
-    public function getCustomCss() 
-    {
-        return $this->getConstant('CUSTOM_CSS', null);
-    }
-    
-    /**
-     * @return boolean
-     */
-    public function getUiLanguageDropdown() 
-    {
-        return $this->getConstant('UI_LANGUAGE_DROPDOWN', FALSE);
-    }
-    
-    /**
-     * @return string
-     */
-    public function getBaseHref() 
-    {
-        return $this->getConstant('BASE_HREF', null);
-    }
-    
-    /**
-     * @return string
-     */
-    public function getGlobalPlugins() 
-    {
-        return explode(' ', $this->getConstant('GLOBAL_PLUGINS', null));
-    }
-    
-    /**
-     * @return boolean
-     */
-    public function getHoneypotEnabled()
-    {
-        return $this->getConstant('UI_HONEYPOT_ENABLED', TRUE);
-    }
-
-    /**
-     * @return integer
-     */
-    public function getHoneypotTime()
-    {
-        return $this->getConstant('UI_HONEYPOT_TIME', 5);
-    }
-    
-}
+<?php
+
+/**
+ * GlobalConfig provides access to the Skosmos configuration in config.inc.
+ */
+class GlobalConfig {
+    private $languages;
+
+    public function __construct($config_name='/../config.inc') 
+    {
+        try {
+            $file_path = dirname(__FILE__) . $config_name;
+            if (!file_exists($file_path)) {
+                throw new Exception('config.inc file is missing, please provide one.');
+            }
+            require_once($file_path);
+            if (isset($LANGUAGES)) {
+                $this->languages = $LANGUAGES;
+            }
+        } catch (Exception $e) {
+            echo "Error: " . $e->getMessage();
+            return;
+        }
+    }
+    
+    private function getConstant($name, $default)
+    {
+        if (defined($name) && constant($name)) {
+            return constant($name);
+        }
+        return $default;
+    }
+
+    /**
+     * Returns the UI languages specified in the configuration or defaults to
+     * only show English
+     * @return array 
+     */
+    public function getLanguages() 
+    {
+        if ($this->languages) {
+            return $this->languages;
+        }
+        return array('en' => 'en_GB.utf8');
+    }
+    
+    /**
+     * Returns the vocabulary configuration file specified the configuration
+     * or vocabularies.ttl if not found.
+     * @return string
+     */
+    public function getVocabularyConfigFile() 
+    {
+        return $this->getConstant('VOCABULARIES_FILE', 'vocabularies.ttl');
+    }
+    
+    /**
+     * Returns the external HTTP request timeout in seconds or the default value
+     * of 5 seconds if not specified in the configuration.
+     * @return integer
+     */
+    public function getHttpTimeout() 
+    {
+        return $this->getConstant('HTTP_TIMEOUT', 5);
+    }
+    
+    /**
+     * Returns the SPARQL HTTP request timeout in seconds or the default value
+     * of 20 seconds if not specified in the configuration.
+     * @return integer
+     */
+    public function getSparqlTimeout() 
+    {
+        return $this->getConstant('SPARQL_TIMEOUT', 20);
+    }
+    
+    /**
+     * Returns the sparql endpoint address defined in the configuration. If
+     * not then defaulting to http://localhost:3030/ds/sparql 
+     * @return string
+     */
+    public function getDefaultEndpoint() 
+    {
+        return $this->getConstant('DEFAULT_ENDPOINT', 'http://localhost:3030/ds/sparql');
+    }
+    
+    /**
+     * @return string
+     */
+    public function getSparqlGraphStore() 
+    {
+        return $this->getConstant('SPARQL_GRAPH_STORE', null);
+    }
+    
+    /**
+     * Returns the maximum number of items to return in transitive queries if defined
+     * in the configuration or the default value of 1000.
+     * @return integer 
+     */
+    public function getDefaultTransitiveLimit() 
+    {
+        return $this->getConstant('DEFAULT_TRANSITIVE_LIMIT', 1000);
+    }
+    
+    /**
+     * Returns the maximum number of items to load at a time if defined
+     * in the configuration or the default value of 20.
+     * @return integer 
+     */
+    public function getSearchResultsSize() 
+    {
+        return $this->getConstant('SEARCH_RESULTS_SIZE', 20);
+    }
+    
+    /**
+     * Returns the configured location for the twig template cache and if not
+     * defined defaults to "/tmp/skosmos-template-cache"
+     * @return string
+     */
+    public function getTemplateCache() 
+    {
+        return $this->getConstant('TEMPLATE_CACHE', 'tmp/skosmos-template-cache');
+    }
+    
+    /**
+     * Returns the defined sparql-query extension eg. "JenaText" or 
+     * if not defined falling back to SPARQL 1.1
+     * @return string
+     */
+    public function getDefaultSparqlDialect() 
+    {
+        return $this->getConstant('DEFAULT_SPARQL_DIALECT', 'Generic');
+    }
+
+    /**
+     * Returns the feedback address defined in the configuration.
+     * @return string
+     */
+    public function getFeedbackAddress() 
+    {
+        return $this->getConstant('FEEDBACK_ADDRESS', null);
+    }
+    
+    /**
+     * Returns true if exception logging has been configured.
+     * @return boolean 
+     */
+    public function getLogCaughtExceptions() 
+    {
+        return $this->getConstant('LOG_CAUGHT_EXCEPTIONS', FALSE);
+    }
+    
+    /**
+     * Returns true if browser console logging has been enabled,
+     * @return boolean
+     */
+    public function getLoggingBrowserConsole()
+    {
+        return $this->getConstant('LOG_BROWSER_CONSOLE', FALSE);
+    }
+
+    /**
+     * Returns the name of a log file if configured, or NULL otherwise.
+     * @return string
+     */
+    public function getLoggingFilename()
+    {
+        return $this->getConstant('LOG_FILE_NAME', null);
+    }
+
+    /**
+     * @return string
+     */
+    public function getServiceName() 
+    {
+        return $this->getConstant('SERVICE_NAME', 'Skosmos');
+    }
+    
+    /**
+     * @return string
+     */
+    public function getServiceTagline() 
+    {
+        return $this->getConstant('SERVICE_TAGLINE', null);
+    }
+    
+    /**
+     * @return string
+     */
+    public function getServiceLogo() 
+    {
+        return $this->getConstant('SERVICE_LOGO', null);
+    }
+    
+    /**
+     * @return string
+     */
+    public function getCustomCss() 
+    {
+        return $this->getConstant('CUSTOM_CSS', null);
+    }
+    
+    /**
+     * @return boolean
+     */
+    public function getUiLanguageDropdown() 
+    {
+        return $this->getConstant('UI_LANGUAGE_DROPDOWN', FALSE);
+    }
+    
+    /**
+     * @return string
+     */
+    public function getBaseHref() 
+    {
+        return $this->getConstant('BASE_HREF', null);
+    }
+    
+    /**
+     * @return string
+     */
+    public function getGlobalPlugins() 
+    {
+        return explode(' ', $this->getConstant('GLOBAL_PLUGINS', null));
+    }
+    
+    /**
+     * @return boolean
+     */
+    public function getHoneypotEnabled()
+    {
+        return $this->getConstant('UI_HONEYPOT_ENABLED', TRUE);
+    }
+
+    /**
+     * @return integer
+     */
+    public function getHoneypotTime()
+    {
+        return $this->getConstant('UI_HONEYPOT_TIME', 5);
+    }
+    
+}
diff --git a/model/Model.php b/model/Model.php
index 2452b2109..cda20781a 100644
--- a/model/Model.php
+++ b/model/Model.php
@@ -57,7 +57,6 @@ public function __construct($config)
     public function getConfig() {
       return $this->globalConfig;
     }
-
     /**
      * Initializes the configuration from the vocabularies.ttl file
      */
diff --git a/model/Vocabulary.php b/model/Vocabulary.php
index 194a0f64d..44b46c4ec 100644
--- a/model/Vocabulary.php
+++ b/model/Vocabulary.php
@@ -229,6 +229,21 @@ public function getDefaultConceptScheme()
         return array_pop($conceptSchemeURIs);
     }
 
+    /**
+     * Return the URI of the default concept scheme of this vocabulary, as set in the vocabulary configuration, or null
+     * if not set.
+     * @return string default concept scheme URI, or null if undefined
+     **/
+
+    public function getMainConceptScheme(){
+        $conceptScheme = $this->resource->get("skosmos:mainConceptScheme");
+        if ($conceptScheme) {
+            return $conceptScheme->getUri();
+        }else{
+            return null;
+        }
+    }
+
     /**
      * Return the top concepts of a concept scheme in the vocabulary.
      * @param string $conceptScheme URI of concept scheme whose top concepts to return. If not set,
diff --git a/model/sparql/GenericSparql.php b/model/sparql/GenericSparql.php
index 544229b6e..2ce6511c4 100644
--- a/model/sparql/GenericSparql.php
+++ b/model/sparql/GenericSparql.php
@@ -31,6 +31,9 @@ class GenericSparql {
      */
     private $qnamecache = array();
 
+
+    
+
     /**
      * Requires the following three parameters.
      * @param string $endpoint SPARQL endpoint address.
@@ -595,9 +598,14 @@ public function queryConceptScheme($conceptscheme) {
     private function generateQueryConceptSchemesQuery($lang) {
         $fcl = $this->generateFromClause();
         $query = <<<EOQ
-SELECT ?cs ?label ?preflabel ?title $fcl
+SELECT ?cs ?label ?preflabel ?title ?domain ?domainLabel $fcl
 WHERE {
  ?cs a skos:ConceptScheme .
+ OPTIONAL{
+    ?cs dcterms:subject ?domain.
+    ?domain skos:prefLabel ?domainLabel.
+    FILTER(langMatches(lang(?domainLabel), '$lang'))
+}
  OPTIONAL {
    ?cs rdfs:label ?label .
    FILTER(langMatches(lang(?label), '$lang'))
@@ -612,7 +620,8 @@ private function generateQueryConceptSchemesQuery($lang) {
    { ?cs dc:title ?title }
    FILTER(langMatches(lang(?title), '$lang'))
  }
-} ORDER BY ?cs
+} 
+ORDER BY ?cs
 EOQ;
         return $query;
     }
@@ -624,7 +633,9 @@ private function generateQueryConceptSchemesQuery($lang) {
      */
     private function transformQueryConceptSchemesResults($result) {
         $ret = array();
+    
         foreach ($result as $row) {
+
             $conceptscheme = array();
             if (isset($row->label)) {
                 $conceptscheme['label'] = $row->label->getValue();
@@ -637,6 +648,11 @@ private function transformQueryConceptSchemesResults($result) {
             if (isset($row->title)) {
                 $conceptscheme['title'] = $row->title->getValue();
             }
+            // add dcterms:subject and their labels in the result
+            if(isset($row->domain) && isset($row->domainLabel)){
+                $conceptscheme['subject']['uri']=$row->domain->getURI();
+                $conceptscheme['subject']['prefLabel']=$row->domainLabel->getValue();
+            }
 
             $ret[$row->cs->getURI()] = $conceptscheme;
         }
@@ -1066,6 +1082,7 @@ private function transformConceptSearchResult($row, $vocabs, $fields)
             $hit['prefLabel'] = $row->label->getValue();
         }
 
+
         if (isset($row->label)) {
             $hit['lang'] = $row->label->getLang();
         }
@@ -1743,7 +1760,8 @@ private function generateParentListQuery($uri, $lang, $fallback, $props) {
         $propertyClause = implode('|', $props);
         $query = <<<EOQ
 SELECT ?broad ?parent ?member ?children ?grandchildren
-(SAMPLE(?lab) as ?label) (SAMPLE(?childlab) as ?childlabel) (SAMPLE(?topcs) AS ?top) (SAMPLE(?nota) as ?notation) (SAMPLE(?childnota) as ?childnotation) $fcl
+(SAMPLE(?lab) as ?label) (SAMPLE(?childlab) as ?childlabel) (GROUP_CONCAT(?topcs; separator=" ") as ?tops) 
+(SAMPLE(?nota) as ?notation) (SAMPLE(?childnota) as ?childnotation) $fcl
 WHERE {
   <$uri> a skos:Concept .
   OPTIONAL {
@@ -1756,7 +1774,8 @@ private function generateParentListQuery($uri, $lang, $fallback, $props) {
       ?broad skos:prefLabel ?lab .
       FILTER (langMatches(lang(?lab), "$fallback"))
     }
-    OPTIONAL { # fallback - other language case
+    OPTIONAL { 
+        # fallback - other language case#
       ?broad skos:prefLabel ?lab .
     }
     OPTIONAL { ?broad skos:notation ?nota . }
@@ -1770,7 +1789,8 @@ private function generateParentListQuery($uri, $lang, $fallback, $props) {
         ?children skos:prefLabel ?childlab .
         FILTER (langMatches(lang(?childlab), "$fallback"))
       }
-      OPTIONAL { # fallback - other language case
+      OPTIONAL { 
+        # fallback - other language case#
         ?children skos:prefLabel ?childlab .
       }
       OPTIONAL {
@@ -1795,6 +1815,7 @@ private function generateParentListQuery($uri, $lang, $fallback, $props) {
     private function transformParentListResults($result, $lang)
     {
         $ret = array();
+        $topConceptsList=array();
         foreach ($result as $row) {
             if (!isset($row->broad)) {
                 // existing concept but no broaders
@@ -1807,8 +1828,10 @@ private function transformParentListResults($result, $lang)
             if (isset($row->exact)) {
                 $ret[$uri]['exact'] = $row->exact->getUri();
             }
-            if (isset($row->top)) {
-                $ret[$uri]['top'] = $row->top->getUri();
+            if (isset($row->tops)) {
+               $topConceptsList=explode(" ", $row->tops->getValue());
+               sort($topConceptsList);
+               $ret[$uri]['tops'] =$topConceptsList;
             }
             if (isset($row->children)) {
                 if (!isset($ret[$uri]['narrower'])) {
diff --git a/resource/js/hierarchy.js b/resource/js/hierarchy.js
index 19b069381..86b5fe85c 100644
--- a/resource/js/hierarchy.js
+++ b/resource/js/hierarchy.js
@@ -128,22 +128,68 @@ function createConceptObject(conceptUri, conceptData) {
  * @param {Object} parentData 
  */
 function attachTopConceptsToSchemes(schemes, currentNode, parentData) {
+  var foundFirstLevel = false;
+
   for (var i = 0; i < schemes.length; i++) {
-    if (schemes[i].uri === parentData[currentNode.uri].top) {
-      if(Object.prototype.toString.call(schemes[i].children) !== '[object Array]' ) {
-        schemes[i].children = [];
-      }
-      schemes[i].children.push(currentNode);
-      // the hierarchy response contains the parent info before the topConcepts so it's a safe to open the first one without broaders 
-      if (!schemes.opened && !currentNode.broader) {
-        schemes[i].state = currentNode.state;
-        schemes.opened = true;
-      }
-    }
+	  foundFirstLevel = true;
+	  
+	  // search if top concept uri is equal to scheme uri on first level
+	  // search in all the 'tops' key
+	  for (var j = 0; j < parentData[currentNode.uri].tops.length; j++) {
+		  var currentTop = parentData[currentNode.uri].tops[j];
+		  // we found a scheme at the first level that is equal to one of the 'tops' value
+		  if(schemes[i].uri===currentTop){			  
+			  if(Object.prototype.toString.call(schemes[i].children) !== '[object Array]' ) {
+				  schemes[i].children = [];
+			  }
+			  // append to a first-level node that corresponds to a concept scheme
+			  schemes[i].children.push(currentNode);
+
+			  // the hierarchy response contains the parent info before the topConcepts so it's a safe to open the first one without broaders 
+			  if (!schemes[i].opened && !currentNode.broader) {
+				  schemes[i].state = currentNode.state;
+				  schemes.opened = true;
+			  }
+			  break;
+		  }
+	  }
+
+	  // search if top concept uri is equal to scheme children uri, if there are children (second level)
+	  // this may be the case if schemes are organised by subjects : subjects will be first-level nodes, concepts schemes will be second level
+	  for (var h = 0; h <schemes[i].children.length; h++) {
+		  // one of the second-level node, actually corresponding to a concept scheme inside a 'domain' node
+		  var currentScheme = schemes[i].children[h];	
+		  
+		  // search in all the 'tops' key
+		  for (var j = 0; j < parentData[currentNode.uri].tops.length; j++) {
+			  var currentTop = parentData[currentNode.uri].tops[j];
+			  
+			  // we found a scheme at the second level that is equal to one of the 'tops' value
+			  if(currentScheme.uri===currentTop) {
+				  if(Object.prototype.toString.call(currentScheme.children) !== '[object Array]' ) {
+					  currentScheme.children = [];
+				  }
+				  currentScheme.children.push(currentNode);
+
+				  // the hierarchy response contains the parent info before the topConcepts so it's a safe to open the first one without broaders 
+				  if (!currentScheme.opened && !currentNode.broader) {
+					  // open the first-level node and second-level node
+					  schemes[i].state = currentNode.state;
+					  currentScheme.state=schemes[i].state;
+					  currentScheme.opened=true;
+					  currentScheme.children.opened=true;
+				  }
+				  break;
+			  }
+		  }
+	  }
+       
   }
+
   return schemes;
 }
 
+
 /*
  * For building a parent hierarchy tree from the leaf concept to the ontology/vocabulary root.
  * @param {String} uri
@@ -151,53 +197,57 @@ function attachTopConceptsToSchemes(schemes, currentNode, parentData) {
  * @param {Object} schemes 
  */
 function buildParentTree(uri, parentData, schemes) {
-  if (parentData === undefined || parentData === null) { return; }
-
-  var loopIndex = 0, // for adding the last concept as a root if no better candidates have been found.
-    currentNode,
-    rootArray = (schemes.length > 1) ? schemes : [];
-
-  for(var conceptUri in parentData) {
-    if (parentData.hasOwnProperty(conceptUri)) {
-      var branchHelper, 
-        exactMatchFound;
-      currentNode = createConceptObject(conceptUri, parentData[conceptUri]);
-      /* if a node has the property topConceptOf set it as the root node. 
-       * Or just setting the last node as a root if nothing else has been found 
-       */
-      if (parentData[conceptUri].top || ( loopIndex === Object.size(parentData)-1) && rootArray.length === 0 || !currentNode.parents && rootArray.length === 0) { 
-        if (rootArray.length === 0) {  
-          branchHelper = currentNode;
-        }
-        // if there are multiple concept schemes attach the topConcepts to the concept schemes
-        if (schemes.length > 1 && (parentData[conceptUri].top)) {
-          schemes = attachTopConceptsToSchemes(schemes, currentNode, parentData);
-        }
-        else {
-          rootArray.push(currentNode);
-        }
-      }
-      if (exactMatchFound) { // combining branches if we have met a exact match during the previous iteration.
-        currentNode.children.push(branchHelper); 
-        branchHelper = undefined;
-        exactMatchFound = false;
-      }
-      // here we have iterated far enough to find the merging point of the trees.
-      if (branchHelper && parentData[branchHelper.uri].exact === currentNode.uri) {
-        exactMatchFound = true;
-      } 
-      setNode(currentNode);
-      loopIndex++;
-    }
-  }
+	if (parentData === undefined || parentData === null) { return; }
+
+	var loopIndex = 0, // for adding the last concept as a root if no better candidates have been found.
+	currentNode,
+	rootArray = (schemes.length > 1) ? schemes : [];
+	//	console.log(JSON.stringify(parentData, null, 4));
+	for(var conceptUri in parentData) {
+		if (parentData.hasOwnProperty(conceptUri)) {
+			var branchHelper, 
+			exactMatchFound;
+			currentNode = createConceptObject(conceptUri, parentData[conceptUri]);
+			/* if a node has the property topConceptOf set it as the root node. 
+			 * Or just setting the last node as a root if nothing else has been found 
+			 */
+			if (parentData[conceptUri].top || ( loopIndex === Object.size(parentData)-1) && rootArray.length === 0 || !currentNode.parents && rootArray.length === 0) { 
+				if (rootArray.length === 0) {  
+					branchHelper = currentNode;
+				}
+				// if there are multiple concept schemes attach the topConcepts to the concept schemes
+				if (schemes.length > 1 && (parentData[conceptUri].top)) {
+					schemes = attachTopConceptsToSchemes(schemes, currentNode, parentData);
 
-  // Iterating over the nodes to make sure all concepts have their children set.
-  appendChildrenToParents();
-  // avoiding the issue with multiple inheritance by deep copying the whole tree object before giving it to jsTree
-  return JSON.parse(JSON.stringify(rootArray));
+				}
+				else {
+					rootArray.push(currentNode);
+				}
+			}
+			if (exactMatchFound) { // combining branches if we have met a exact match during the previous iteration.
+				currentNode.children.push(branchHelper); 
+				branchHelper = undefined;
+				exactMatchFound = false;
+			}
+			// here we have iterated far enough to find the merging point of the trees.
+			if (branchHelper && parentData[branchHelper.uri].exact === currentNode.uri) {
+				exactMatchFound = true;
+			} 
+			setNode(currentNode);
+			loopIndex++;
+		}
+	}
+
+	// Iterating over the nodes to make sure all concepts have their children set.
+	appendChildrenToParents();
+	// avoiding the issue with multiple inheritance by deep copying the whole tree object before giving it to jsTree
+	
+	// console.log(JSON.stringify(rootArray, null, 4));
+	return JSON.parse(JSON.stringify(rootArray));
 }
 
 function getConceptHref(conceptData) {
+	
   if (conceptData.uri.indexOf(window.uriSpace) !== -1) {
     var page = conceptData.uri.substr(window.uriSpace.length);
     if (/[^a-zA-Z0-9\.]/.test(page) || page.indexOf("/") > -1 ) {
@@ -259,19 +309,22 @@ function appendChildrenToParents() {
 
 function createObjectsFromNarrowers(narrowerResponse) {
   var childArray = [];
-  for (var i = 0; i < narrowerResponse.narrower.length; i++) {
-    var conceptObject = narrowerResponse.narrower[i];
-    var childObject = {
-      text : getLabel(conceptObject), 
-      a_attr : getConceptHref(conceptObject),
-      uri: conceptObject.uri,
-      parents: narrowerResponse.uri,
-      state: { opened: false, disabled: false, selected: false }
-    };
-    childObject.children = conceptObject.hasChildren ? true : false;
-    setNode(childObject);
-    childArray.push(childObject);
-  }
+     
+        for (var i = 0; i < narrowerResponse.narrower.length; i++) {
+        var conceptObject = narrowerResponse.narrower[i];
+        var childObject = {
+          text : getLabel(conceptObject), 
+          a_attr : getConceptHref(conceptObject),
+          uri: conceptObject.uri,
+          parents: narrowerResponse.uri,
+          state: { opened: false, disabled: false, selected: false }
+        };
+        childObject.children = conceptObject.hasChildren ? true : false;
+        setNode(childObject);
+        childArray.push(childObject);
+      }
+
+  
   return childArray;
 }
 
@@ -281,7 +334,7 @@ function getParams(node) {
   return $.param({'uri' : nodeId, 'lang' : clang});
 }
 
-function pickLabelFromScheme(scheme) {
+function pickLabel(scheme) {
   var label = '';
   if (scheme.prefLabel)
     label = scheme.prefLabel;
@@ -294,20 +347,96 @@ function pickLabelFromScheme(scheme) {
 
 function schemeRoot(schemes) {
   var topArray = [];
+  
+  
+  // Step 1 : gather domain list
+  var domains=[];
   for (var i = 0; i < schemes.length; i++) {
-    var scheme = schemes[i];
-    var label = pickLabelFromScheme(scheme);
-    if (label !== '') { // hiding schemes without a label/title
-      var schemeObject = {
-        text: label, 
-        a_attr : { "href" : vocab + '/' + lang + '/page/?uri=' + scheme.uri, 'class': 'scheme'},
-        uri: scheme.uri,
-        children: true,
-        state: { opened: false } 
-      };
-      topArray.push(schemeObject);
+    if(schemes[i].subject != null) {
+        var schemeDomain = schemes[i].subject.uri;
+
+        // test if domain was already found  
+        var found = false;
+        for (var k = 0; k < domains.length; k++) {
+          if(domains[k].uri===schemeDomain){
+            found = true;
+            break;
+          }
+        }
+
+        // if not found, store it in domain list
+        if(!found) {
+          domains.push(schemes[i].subject);
+        }
     }
   }
+
+  // Step 2 : create tree nodes for each domain
+ 
+  for (var i = 0; i < domains.length; i++) {
+    var theDomain = domains[i];
+    var theDomainLabel = pickLabel(theDomain);
+    
+    // avoid creating entries with empty labels
+    if(theDomainLabel != '') {        
+        // Step 2.1 : create domain node without children
+        var domainObject = {
+        		text: theDomainLabel, 
+        		// note that the class 'domain' will make sure the node will be sorted _before_ others (see the 'sort' functio nat the end)
+        		a_attr : { "href" : vocab + '/' + lang + '/page/?uri=' + theDomain.uri, 'class': 'domain'},
+        		uri: theDomain.uri,
+        		children: [],
+        		state: { opened: false } 
+        };
+
+        // Step 2.2 : find the concept schemes in this domain and add them as children
+        for (var k = 0; k < schemes.length; k++) {
+        	var theScheme = schemes[k];
+        	var theSchemeLabel = pickLabel(theScheme);
+        	
+        	// avoid creating entries with empty labels
+        	if(theSchemeLabel != '') { 
+	        	if((theScheme.subject) != null && (theScheme.subject.uri===theDomain.uri)) {
+	        		domainObject.children.push(
+	        				{
+	        					text: theSchemeLabel,
+	        					a_attr:{ "href" : vocab + '/' + lang + '/page/?uri=' + theScheme.uri, 'class': 'scheme'},
+	        					uri: theScheme.uri,
+	        					children: true,
+	        					state: { opened: false } 
+	        				}
+	        		);
+	        	}
+        	}
+        }
+        topArray.push(domainObject);   	
+    }
+
+  }
+
+  // Step 3 : add the schemes without any subjects after the subjects node
+  for (var k = 0; k < schemes.length; k++) {
+	  var theScheme = schemes[k]; 
+	  
+	  if(theScheme.subject == null) {		  
+		  // avoid creating entries with empty labels
+		  var theSchemeLabel = pickLabel(theScheme);
+		  if(theSchemeLabel != '') { 		  
+			  topArray.push(
+					  {
+						  text:theSchemeLabel,
+						  a_attr:{ "href" : vocab + '/' + lang + '/page/?uri=' + theScheme.uri, 'class': 'scheme'},
+						  uri: theScheme.uri,
+						  children: true,
+						  state: { opened: false } 
+					  }
+			  );
+		  }
+	  }
+  }
+  
+  // console.log(JSON.stringify(topArray, null, 4));
+
   return topArray;
 }
 
@@ -325,6 +454,7 @@ function addConceptsToScheme(topConcept, childObject, schemes) {
   return schemes;
 }
 
+
 function topConceptsToSchemes(topConcepts, schemes) {
   var childArray = schemes.length > 1 ? schemes : [];
   for (var i in topConcepts) {
@@ -427,7 +557,29 @@ function getTreeConfiguration() {
         }
     },
     'plugins' : ['sort'],
-    'sort' : function (a,b) { return naturalCompare(this.get_text(a).toLowerCase(), this.get_text(b).toLowerCase()); }
+    'sort' : function (a,b) {
+    	var nodeA = this.get_node(a);
+        var nodeB = this.get_node(b);
+        // make sure the tree nodes with class 'domain' are sorted before the others
+    	if(nodeA.a_attr && nodeA.a_attr['class']) {
+    		if(nodeB.a_attr && nodeB.a_attr['class']) {
+    			if(nodeA.a_attr['class'] == 'domain' && nodeB.a_attr['class'] == 'domain') {
+    				return naturalCompare(this.get_text(a).toLowerCase(), this.get_text(b).toLowerCase());
+    			}
+    			else if(nodeA.a_attr['class'] == 'domain' && nodeB.a_attr['class'] != 'domain') {
+    				return -1;
+    			}
+    			else if(nodeA.a_attr['class'] != 'domain' && nodeB.a_attr['class'] == 'domain') {
+    				return 1;
+    			}
+    		} else {
+    			return naturalCompare(this.get_text(a).toLowerCase(), this.get_text(b).toLowerCase());
+    		}
+    	}  else {
+    		return naturalCompare(this.get_text(a).toLowerCase(), this.get_text(b).toLowerCase());
+    	}
+    	// return naturalCompare(this.get_text(a).toLowerCase(), this.get_text(b).toLowerCase());
+     }
   });
 }
 
diff --git a/rest.php b/rest.php
index 6b0e5ea89..b964ddfa2 100644
--- a/rest.php
+++ b/rest.php
@@ -7,6 +7,7 @@
 
 header("Access-Control-Allow-Origin: *"); // enable CORS for the whole REST API
 
+
 try {
     $config = new GlobalConfig();
     $model = new Model($config);
diff --git a/tests/GenericSparqlTest.php b/tests/GenericSparqlTest.php
index 7afc2065e..c3d2144fd 100644
--- a/tests/GenericSparqlTest.php
+++ b/tests/GenericSparqlTest.php
@@ -350,6 +350,49 @@ public function testQueryConceptSchemes()
       $this->assertEquals('Test conceptscheme', $label['label']);
     }
   }
+  
+  /**
+   * @covers GenericSparql::queryConceptSchemes
+   * @covers GenericSparql::generateQueryConceptSchemesQuery
+   * @covers GenericSparql::transformQueryConceptSchemesResults
+   */
+  public function testQueryConceptSchemesSubject()
+  {
+      $sparql = new GenericSparql('http://localhost:3030/ds/sparql', 'http://www.skosmos.skos/test-concept-schemes/', $this->model);
+      
+      $actual = $sparql->queryConceptSchemes('en');
+      $expected = array(
+          'http://exemple.fr/domains' => array(
+              'prefLabel' => 'Special Domains Concept Scheme'
+          ),
+          'http://exemple.fr/mt1' => array(
+              'prefLabel' => 'Micro-Thesaurus 1',
+              'subject' => array(
+                  'uri' => 'http://exemple.fr/d1',
+                  'prefLabel' => 'Domain 1'
+              )
+          ),
+          'http://exemple.fr/mt2' => array(
+              'prefLabel' => 'Micro-Thesaurus 2',
+              'subject' => array(
+                  'uri' => 'http://exemple.fr/d1',
+                  'prefLabel' => 'Domain 1'
+              )
+          ),
+          'http://exemple.fr/mt3' => array(
+              'prefLabel' => 'Micro-Thesaurus 3',
+              'subject' => array(
+                  'uri' => 'http://exemple.fr/d2',
+                  'prefLabel' => 'Domain 2'
+              )
+          ),
+          'http://exemple.fr/thesaurus' => array(
+              'prefLabel' => 'The Thesaurus'
+          ),
+      );
+      
+      $this->assertEquals($expected, $actual);
+  }
 
   /**
    * @covers GenericSparql::queryConcepts
@@ -738,7 +781,7 @@ public function testQueryParentList()
     );
     $props = array (
       'uri' => 'http://www.skosmos.skos/test/ta1',
-      'top' => 'http://www.skosmos.skos/test/conceptscheme',
+      'tops' => array('http://www.skosmos.skos/test/conceptscheme'),
       'prefLabel' => 'Fish',
     );
     $narrowers = array (
diff --git a/tests/VocabularyTest.php b/tests/VocabularyTest.php
index cf5eebb2b..36764fd00 100644
--- a/tests/VocabularyTest.php
+++ b/tests/VocabularyTest.php
@@ -434,6 +434,6 @@ public function testGetConceptInfo() {
     $this->assertInstanceOf('Concept', $concept[0]);
     $this->assertEquals(1, sizeof($concept));
   }
-
+  
 }
 
diff --git a/tests/test-vocab-data/test-concept-schemes.ttl b/tests/test-vocab-data/test-concept-schemes.ttl
new file mode 100644
index 000000000..9dca0ce4d
--- /dev/null
+++ b/tests/test-vocab-data/test-concept-schemes.ttl
@@ -0,0 +1,56 @@
+@prefix skos: <http://www.w3.org/2004/02/skos/core#>.
+@prefix ex: <http://exemple.fr/>.
+@prefix dcterms: <http://purl.org/dc/terms/>.
+
+ex:thesaurus a skos:ConceptScheme ;
+	skos:prefLabel "The Thesaurus"@en .
+
+ex:mt1 a skos:ConceptScheme ;
+	skos:prefLabel "Micro-Thesaurus 1"@en ;
+	dcterms:subject ex:d1 .
+
+ex:mt2 a skos:ConceptScheme ;
+	skos:prefLabel "Micro-Thesaurus 2"@en ;
+	dcterms:subject ex:d1 .
+
+ex:mt3 a skos:ConceptScheme ;
+	skos:prefLabel "Micro-Thesaurus 3"@en ;
+	dcterms:subject ex:d2 .
+
+### Begin Domains
+
+ex:domains a skos:ConceptScheme ;
+	skos:prefLabel "Special Domains Concept Scheme"@en .
+
+ex:d1 a skos:Concept ;
+	skos:inScheme ex:domains ;
+	skos:topConceptOf ex:domains ;
+	skos:prefLabel "Domain 1"@en .
+
+ex:d2 a skos:Concept ;
+	skos:inScheme ex:domains ;
+	skos:topConceptOf ex:domains ;
+	skos:prefLabel "Domain 2"@en .
+
+#### End Domains
+
+ex:c1 a skos:Concept ;
+	skos:prefLabel "Concept 1"@en ;
+	skos:inScheme ex:thesaurus , ex:mt1 ;
+	skos:topConceptOf ex:thesaurus , ex:mt1 ;
+	skos:narrower ex:c1.1 .
+
+ex:c1.1 a skos:Concept ;
+	skos:prefLabel "Concept 1.1"@en ;
+	skos:inScheme ex:thesaurus , ex:mt1 ;
+	skos:broader ex:c1 .
+
+ex:c2 a skos:Concept ;
+	skos:prefLabel "Concept 2"@en ;
+	skos:inScheme ex:thesaurus , ex:mt2 ;
+	skos:topConceptOf ex:thesaurus , ex:mt2 .
+
+ex:c3 a skos:Concept ;
+	skos:prefLabel "Concept 3"@en ;
+	skos:inScheme ex:thesaurus , ex:mt3 ;
+	skos:topConceptOf ex:thesaurus , ex:mt3 .
\ No newline at end of file
diff --git a/tests/testvocabularies.ttl b/tests/testvocabularies.ttl
index 69ce68b97..0eadcff52 100644
--- a/tests/testvocabularies.ttl
+++ b/tests/testvocabularies.ttl
@@ -65,6 +65,19 @@
 	skosmos:sparqlGraph <http://www.skosmos.skos/groups/> .
 
 
+:test-concept-schemes a skosmos:Vocabulary, void:Dataset ;
+	dc11:title "Test concept schemes"@en ;
+	dc:subject :cat_general ;
+	void:dataDump <http://skosmos.skos/dump/test/test-concept-schemes.ttl>,
+		<http://skosmos.skos/dump/test/test-concept-schemes> ;
+	void:uriSpace "http://www.exemple.fr/";
+	skosmos:arrayClass isothes:ThesaurusArray ;
+ 	 skosmos:groupClass skos:Collection ;
+	void:sparqlEndpoint <http://localhost:3030/ds/sparql> ;
+	skosmos:language "en";
+	skosmos:defaultLanguage "en";
+	skosmos:sparqlGraph <http://www.skosmos.skos/test-concept-schemes/> .
+
 :showDeprecated a skosmos:Vocabulary, void:Dataset ;
 	dc11:title "Show deprecated test vocabulary"@en ;
 	dc:subject :cat_general ;