diff --git a/pom.xml b/pom.xml
index 4c294de..dcd0360 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>fr.insee.knowledge</groupId>
     <artifactId>knowledge</artifactId>
-    <version>0.5.0</version>
+    <version>0.5.1</version>
     <packaging>jar</packaging>
     <name>Knowledge-Back-Office</name>
     <description>Back-office services for Knowledge</description>
diff --git a/src/main/java/fr/insee/knowledge/domain/Function.java b/src/main/java/fr/insee/knowledge/domain/Function.java
index 72d5498..880eef8 100644
--- a/src/main/java/fr/insee/knowledge/domain/Function.java
+++ b/src/main/java/fr/insee/knowledge/domain/Function.java
@@ -1,7 +1,10 @@
 package fr.insee.knowledge.domain;
 
+import com.fasterxml.jackson.annotation.JsonInclude;
+
 import java.util.List;
 
+@JsonInclude(JsonInclude.Include.NON_EMPTY)
 public class Function extends GenericIDLabel {
     private int dispo;
     private GenericIDLabel gsbpm;
diff --git a/src/main/java/fr/insee/knowledge/domain/hierarchy/Hierarchy.java b/src/main/java/fr/insee/knowledge/domain/hierarchy/Hierarchy.java
index 25aac79..cecd847 100644
--- a/src/main/java/fr/insee/knowledge/domain/hierarchy/Hierarchy.java
+++ b/src/main/java/fr/insee/knowledge/domain/hierarchy/Hierarchy.java
@@ -1,9 +1,11 @@
 package fr.insee.knowledge.domain.hierarchy;
 
+import com.fasterxml.jackson.annotation.JsonInclude;
 import fr.insee.knowledge.domain.GenericIDLabel;
 
 import java.util.List;
 
+@JsonInclude(JsonInclude.Include.NON_EMPTY)
 public class Hierarchy<T extends Hierarchy> extends GenericIDLabel {
     private List<T> children;