diff --git a/unl-tools-core/src/main/java/fr/tetras_libre/unltools/unl/Graph.java b/unl-tools-core/src/main/java/fr/tetras_libre/unltools/unl/Graph.java
index ee6daceea9f0a727f0f20bb9413af94c1034a84d..7112e01f428d077cf4d1a61c5d3177962d12bab5 100644
--- a/unl-tools-core/src/main/java/fr/tetras_libre/unltools/unl/Graph.java
+++ b/unl-tools-core/src/main/java/fr/tetras_libre/unltools/unl/Graph.java
@@ -97,15 +97,17 @@ public class Graph {
         return graphNode;
     }
 
-//    public GraphNode getNodesWithinSubgraph(String graphNumber){
-//        if (null == graphNumber) throw new IllegalArgumentException("GraphNumber cannot be null");
-//
-//        var result = this.relations.stream().filter(e -> graphNumber.equals(e.getSubGraphReferenceLabel())).findFirst().get();
-//        if (null != result.getNode1()) return result.getNode1();
-//        if (null != result.getNode2()) return result.getNode2();
-//
-//        throw new RuntimeException(String.format("Cannot find any graph node within '%s' subgraph", graphNumber));
-//    }
+    public GraphNode getNodesWithinSubgraph(String graphNumber){
+        if (null == graphNumber) throw new IllegalArgumentException("GraphNumber cannot be null");
+
+        var result = this.relations.stream().filter(e -> graphNumber.equals(e.getSubGraphReferenceLabel())).findFirst();
+        if (result.isPresent()) {
+            if (null != result.get().getNode1()) return result.get().getNode1();
+            if (null != result.get().getNode2()) return result.get().getNode2();
+        }
+
+        throw new RuntimeException(String.format("Cannot find any graph node within '%s' subgraph", graphNumber));
+    }
 
     @Override
     public java.lang.String toString() {
diff --git a/unl-tools-infrastructure/src/main/java/fr/tetras_libre/unltools/unl/exporters/dot/DotFileGraphExporter.java b/unl-tools-infrastructure/src/main/java/fr/tetras_libre/unltools/unl/exporters/dot/DotFileGraphExporter.java
index 5811bb5f776ff4ee51666b678449d51dcf6b24f7..9f06cc75d1ee70d43a808298f42759b720f28b87 100644
--- a/unl-tools-infrastructure/src/main/java/fr/tetras_libre/unltools/unl/exporters/dot/DotFileGraphExporter.java
+++ b/unl-tools-infrastructure/src/main/java/fr/tetras_libre/unltools/unl/exporters/dot/DotFileGraphExporter.java
@@ -70,10 +70,9 @@ public class DotFileGraphExporter implements GraphExporter {
      * @param scope The current scope name
      * @param g     The graph to export
      * @throws IOException          An I/O error occurred
-     * @throws NoEntryNodeException Inconsistent nodes reference inside the graph
      * @see IOException
      */
-    private void WriteCluster(String scope, Graph g) throws IOException, NoEntryNodeException {
+    private void WriteCluster(String scope, Graph g) throws IOException {
         writer.append(String.format("subgraph cluster_%s{\n", scope.substring(1)))
                 .append("   color = black;\n")
                 .append(String.format("   label = \"%s\"", scope));
@@ -133,11 +132,10 @@ public class DotFileGraphExporter implements GraphExporter {
      *
      * @param graphRelation A GraphRelation inside graph g
      * @param g             The current graphe to export
-     * @throws NoEntryNodeException One node in graphRelation is not found in g
      * @throws IOException          An I/O error occurred
      * @see IOException
      */
-    private void write(GraphRelation graphRelation, Graph g) throws NoEntryNodeException, IOException {
+    private void write(GraphRelation graphRelation, Graph g) throws IOException {
         GraphNode n1 = graphRelation.getNode1();
         GraphNode n2 = graphRelation.getNode2();
 
@@ -162,16 +160,15 @@ public class DotFileGraphExporter implements GraphExporter {
      * @param g         the global graph
      * @return if graphNode is SubGraphRelationNode the node number of the referenced node in g,
      * otherwise the node number of the current node in graphNode
-     * @throws NoEntryNodeException No corresponding node found in g for the corresponding inside graphNode
      */
-    private String getTextForSubGraphRelationOrGetNodeNumber(GraphNode graphNode, Graph g) throws NoEntryNodeException {
+    private String getTextForSubGraphRelationOrGetNodeNumber(GraphNode graphNode, Graph g) {
         if (graphNode instanceof SubGraphReferenceNode) {
-//            try{
+            try{
                 return Integer.toString(g.getEntryNode(((SubGraphReferenceNode) graphNode).getReferenceNumber()).getNodeNumber());
-//            }
-//            catch (NoEntryNodeException ex){
-//                return Integer.toString(g.getNodesWithinSubgraph(((SubGraphReferenceNode) graphNode).getReferenceNumber()).getNodeNumber());
-//            }
+            }
+            catch (NoEntryNodeException ex){
+                return Integer.toString(g.getNodesWithinSubgraph(((SubGraphReferenceNode) graphNode).getReferenceNumber()).getNodeNumber());
+            }
         } else {
             return Integer.toString(graphNode.getNodeNumber());
         }