diff --git a/lib/lrama/lexer.rb b/lib/lrama/lexer.rb
index d047994a..72ce9019 100644
--- a/lib/lrama/lexer.rb
+++ b/lib/lrama/lexer.rb
@@ -213,21 +213,33 @@ def lex_user_code(ss, line, column, lines)
           string, line = lex_string(ss, "'", line, lines)
           str << string
           next
+
+        # $ references
+        # It need to wrap an identifier with brackets to use ".-" for identifiers
         when ss.scan(/\$(<[a-zA-Z0-9_]+>)?\$/) # $$, $<long>$
           tag = ss[1] ? create_token(Token::Tag, ss[1], line, str.length) : nil
           references << [:dollar, "$", tag, str.length, str.length + ss[0].length - 1]
         when ss.scan(/\$(<[a-zA-Z0-9_]+>)?(\d+)/) # $1, $2, $<long>1
           tag = ss[1] ? create_token(Token::Tag, ss[1], line, str.length) : nil
           references << [:dollar, Integer(ss[2]), tag, str.length, str.length + ss[0].length - 1]
-        when ss.scan(/\$(<[a-zA-Z0-9_]+>)?([a-zA-Z_.][-a-zA-Z0-9_.]*)/) # $foo, $expr, $<long>program
+        when ss.scan(/\$(<[a-zA-Z0-9_]+>)?([a-zA-Z_][a-zA-Z0-9_]*)/) # $foo, $expr, $<long>program (named reference without brackets)
+          tag = ss[1] ? create_token(Token::Tag, ss[1], line, str.length) : nil
+          references << [:dollar, ss[2], tag, str.length, str.length + ss[0].length - 1]
+        when ss.scan(/\$(<[a-zA-Z0-9_]+>)?\[([a-zA-Z_.][-a-zA-Z0-9_.]*)\]/) # $expr.right, $expr-right, $<long>program (named reference with brackets)
           tag = ss[1] ? create_token(Token::Tag, ss[1], line, str.length) : nil
           references << [:dollar, ss[2], tag, str.length, str.length + ss[0].length - 1]
+
+        # @ references
+        # It need to wrap an identifier with brackets to use ".-" for identifiers
         when ss.scan(/@\$/) # @$
           references << [:at, "$", nil, str.length, str.length + ss[0].length - 1]
         when ss.scan(/@(\d+)/) # @1
           references << [:at, Integer(ss[1]), nil, str.length, str.length + ss[0].length - 1]
-        when ss.scan(/@([a-zA-Z_.][-a-zA-Z0-9_.]*)/) # @foo, @expr
+        when ss.scan(/@([a-zA-Z][a-zA-Z0-9_]*)/) # @foo, @expr (named reference without brackets)
+          references << [:at, ss[1], nil, str.length, str.length + ss[0].length - 1]
+        when ss.scan(/@\[([a-zA-Z_.][-a-zA-Z0-9_.]*)\]/) # @expr.right, @expr-right  (named reference with brackets)
           references << [:at, ss[1], nil, str.length, str.length + ss[0].length - 1]
+
         when ss.scan(/{/)
           brace_count += 1
         when ss.scan(/}/)
diff --git a/lib/lrama/lexer/token.rb b/lib/lrama/lexer/token.rb
index 4eca6f60..6221abe0 100644
--- a/lib/lrama/lexer/token.rb
+++ b/lib/lrama/lexer/token.rb
@@ -28,6 +28,7 @@ def numberize_references(lhs, rhs)
               if lhs.referred_by?(ref_name)
                 '$'
               else
+                # TODO: Better error message for wrong reference
                 rhs.find_index {|token| token.referred_by?(ref_name) } + 1
               end
             [ref[0], value, ref[2], ref[3], ref[4]]
diff --git a/spec/lrama/integration_spec.rb b/spec/lrama/integration_spec.rb
index 5f83c3db..a3b22bb9 100644
--- a/spec/lrama/integration_spec.rb
+++ b/spec/lrama/integration_spec.rb
@@ -214,7 +214,7 @@ def test_rules(rules, input, expected, command_args: [], debug: false)
       ]
       cases = generate_lexer_body(input)
 
-      test_grammar(<<~Grammar, "expr[left]: 0.0-0.1. expr[right]: 1.0-1.1. line: 0.0-2.1. => 3")
+      test_grammar(<<~Grammar, "expr[ex-left] (0): 0.0-0.1. expr[ex.right] (1): 1.0-1.1. line (0): 0.0-2.1. => 3")
   %{
   #include <stdio.h>
 
@@ -264,7 +264,7 @@ def test_rules(rules, input, expected, command_args: [], debug: false)
           {
             (void)yynerrs;
 
-            printf("line: ");
+            printf("line (%d): ", @expr.first_line);
             print_location(&@expr);
 
             printf("=> %d", $expr);
@@ -272,15 +272,15 @@ def test_rules(rules, input, expected, command_args: [], debug: false)
       ;
 
   expr[result]: NUM
-              | expr[left] expr[right] '+'
+              | expr[ex-left] expr[ex.right] '+'
                   {
-                    printf("expr[left]: ");
-                    print_location(&@left);
+                    printf("expr[ex-left] (%d): ", @[ex-left].first_line);
+                    print_location(&@[ex-left]);
 
-                    printf("expr[right]: ");
-                    print_location(&@right);
+                    printf("expr[ex.right] (%d): ", @[ex.right].first_line);
+                    print_location(&@[ex.right]);
 
-                    $result = $left + $right;
+                    $result = $[ex-left] + $[ex.right];
                   }
               ;