diff --git a/AlgebraicDataflowArchitectureModel/src/algorithms/JavaCodeGenerator.java b/AlgebraicDataflowArchitectureModel/src/algorithms/JavaCodeGenerator.java
index 7675b30..94d3caf 100644
--- a/AlgebraicDataflowArchitectureModel/src/algorithms/JavaCodeGenerator.java
+++ b/AlgebraicDataflowArchitectureModel/src/algorithms/JavaCodeGenerator.java
@@ -351,46 +351,41 @@
 
 	static private ArrayList<ResourceNode> determineResourceOrder(ResourceDependencyGraph graph) {
 		ArrayList<ResourceNode> resources = new ArrayList<>();
+		Set<ResourceNode> visited = new HashSet<>();
 		for (Node n : graph.getNodes()) {
 			ResourceNode rn = (ResourceNode) n;
-			boolean flag = true;
-			for (Edge e : rn.getOutEdges()) {
-				ResourceDependency re = (ResourceDependency) e;
-				if (((PushPullAttribute) re.getAttribute()).getOptions().get(0) == PushPullValue.PUSH) {
-					flag = false;
-				}
-			}
-			for (Edge e : rn.getInEdges()) {
-				ResourceDependency re = (ResourceDependency) e;
-				if (((PushPullAttribute) re.getAttribute()).getOptions().get(0) != PushPullValue.PUSH) {
-					flag = false;
-				}
-			}
-			if (flag)
-				resources.add(rn);
-		}
-		List<ResourceNode> initialResources = (List<ResourceNode>) resources.clone();
-		for (ResourceNode r: initialResources) {
-			trackNode(r, resources);
+			topologicalSort(graph, rn, visited, resources);
 		}
 		return resources;
 	}
-
-	static private void trackNode(ResourceNode current, ArrayList<ResourceNode> resources) {
-		if (!resources.contains(current))
-			resources.add(current);
-		for (Edge e : current.getOutEdges()) {
-			ResourceDependency re = (ResourceDependency) e;
-			if (((PushPullAttribute) re.getAttribute()).getOptions().get(0) != PushPullValue.PUSH) {
-				trackNode((ResourceNode) re.getDestination(), resources);
-			}
-		}
-		for (Edge e : current.getInEdges()) {
+	
+	static private void topologicalSort(ResourceDependencyGraph graph, ResourceNode curNode, Set<ResourceNode> visited, List<ResourceNode> orderedList) {
+		if (visited.contains(curNode)) return;
+		visited.add(curNode);
+		for (Edge e : curNode.getInEdges()) {
 			ResourceDependency re = (ResourceDependency) e;
 			if (((PushPullAttribute) re.getAttribute()).getOptions().get(0) == PushPullValue.PUSH) {
-				trackNode((ResourceNode) re.getSource(), resources);
+				topologicalSort(graph, (ResourceNode) re.getSource(), visited, orderedList);
 			}
 		}
+		for (Edge e : curNode.getOutEdges()) {
+			ResourceDependency re = (ResourceDependency) e;
+			if (((PushPullAttribute) re.getAttribute()).getOptions().get(0) != PushPullValue.PUSH) {
+				topologicalSort(graph, (ResourceNode) re.getDestination(), visited, orderedList);
+			}
+		}
+		for (Node n: graph.getNodes()) {		// for reference resources.
+			ResourceNode rn = (ResourceNode) n;
+			for (Edge e : rn.getInEdges()) {
+				ResourceDependency re = (ResourceDependency) e;
+				for (ChannelMember m: re.getChannelGenerator().getReferenceChannelMembers()) {
+					if (m.getIdentifierTemplate() == curNode.getIdentifierTemplate()) {
+						topologicalSort(graph, rn, visited, orderedList);
+					}
+				}
+			}
+		}
+		orderedList.add(0, curNode);
 	}
 
 	private static MethodDeclaration getMethod(TypeDeclaration type, String methodName) {
diff --git a/AlgebraicDataflowArchitectureModel/src/algorithms/JavaMethodBodyGenerator.java b/AlgebraicDataflowArchitectureModel/src/algorithms/JavaMethodBodyGenerator.java
index 4278567..6662ab9 100644
--- a/AlgebraicDataflowArchitectureModel/src/algorithms/JavaMethodBodyGenerator.java
+++ b/AlgebraicDataflowArchitectureModel/src/algorithms/JavaMethodBodyGenerator.java
@@ -3,8 +3,10 @@
 import java.util.AbstractMap;
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import code.ast.CompilationUnit;
 import code.ast.MethodDeclaration;
@@ -156,34 +158,36 @@
 						getter.addStatement("return " + resource.getIdentifierTemplate().getResourceName() + ";");
 					}
 					// methods for input events
-					Map.Entry<DataflowChannelGenerator, ChannelMember> ioChannelAndMember = getIOChannelAndMember(resource, model);
-					if (ioChannelAndMember != null) {
-						ChannelMember out = ioChannelAndMember.getValue();
-						Term message = (Term) out.getStateTransition().getMessageExpression();
-						MethodDeclaration input = getMethod(type, message.getSymbol().getName());
-						if (input != null) {
-							String[] sideEffects = new String[] {""};
-							Expression updateExp = ioChannelAndMember.getKey().deriveUpdateExpressionOf(out, JavaCodeGenerator.pushAccessor);
-							String newState = updateExp.toImplementation(sideEffects);
-							String updateStatement;
-							if (updateExp instanceof Term && ((Term) updateExp).getSymbol().isImplWithSideEffect()) {
-								updateStatement = sideEffects[0];	
-							} else {
-								updateStatement = sideEffects[0] + "this." + resourceName + " = " + newState + ";";
-							}
-							if (input.getBody() == null || !input.getBody().getStatements().contains(updateStatement)) {
-								input.addFirstStatement(updateStatement);
-							}
-							if (mainType != null) {
-								MethodDeclaration mainInput = getMethod(mainType, input.getName());
-								if (mainInput != null) {
-									String args = "";
-									String delimitar = "";
-									for (Variable var: message.getVariables().values()) {
-										args += delimitar + var.getName();
-										delimitar = ", ";
+					Map.Entry<DataflowChannelGenerator, Set<ChannelMember>> ioChannelAndMembers = getIOChannelAndMembers(resource, model);
+					if (ioChannelAndMembers != null) {
+						Set<ChannelMember> outs = ioChannelAndMembers.getValue();
+						for (ChannelMember out: outs) {
+							Term message = (Term) out.getStateTransition().getMessageExpression();
+							MethodDeclaration input = getMethod(type, message.getSymbol().getName());
+							if (input != null) {
+								String[] sideEffects = new String[] {""};
+								Expression updateExp = ioChannelAndMembers.getKey().deriveUpdateExpressionOf(out, JavaCodeGenerator.pushAccessor);
+								String newState = updateExp.toImplementation(sideEffects);
+								String updateStatement;
+								if (updateExp instanceof Term && ((Term) updateExp).getSymbol().isImplWithSideEffect()) {
+									updateStatement = sideEffects[0];	
+								} else {
+									updateStatement = sideEffects[0] + "this." + resourceName + " = " + newState + ";";
+								}
+								if (input.getBody() == null || !input.getBody().getStatements().contains(updateStatement)) {
+									input.addFirstStatement(updateStatement);
+								}
+								if (mainType != null) {
+									MethodDeclaration mainInput = getMethod(mainType, input.getName());
+									if (mainInput != null) {
+										String args = "";
+										String delimitar = "";
+										for (Variable var: message.getVariables().values()) {
+											args += delimitar + var.getName();
+											delimitar = ", ";
+										}
+										mainInput.addStatement("this." + resourceName + "." + input.getName() + "(" + args + ");");
 									}
-									mainInput.addStatement("this." + resourceName + "." + input.getName() + "(" + args + ");");
 								}
 							}
 						}
@@ -221,20 +225,24 @@
 		return null;
 	}
 	
-	private static Map.Entry<DataflowChannelGenerator, ChannelMember> getIOChannelAndMember(ResourceNode resource, DataFlowModel model) {
+	private static Map.Entry<DataflowChannelGenerator, Set<ChannelMember>> getIOChannelAndMembers(ResourceNode resource, DataFlowModel model) {
+		Set<ChannelMember> channelMembers = new HashSet<>();
+		DataflowChannelGenerator channel = null;
 		for (ChannelGenerator c: model.getIOChannelGenerators()) {
-			DataflowChannelGenerator channel = (DataflowChannelGenerator) c;
+			DataflowChannelGenerator ch = (DataflowChannelGenerator) c;
 			// I/O channel
-			for (ChannelMember out: channel.getOutputChannelMembers()) {
+			for (ChannelMember out: ch.getOutputChannelMembers()) {
 				if (out.getIdentifierTemplate().equals(resource.getIdentifierTemplate())) {
 					if (out.getStateTransition().getMessageExpression() instanceof Term) {
 						// not an identity element
-						return new AbstractMap.SimpleEntry<>(channel, out);
+						channel = ch;
+						channelMembers.add(out);
 					}
 				}
 			}
 		}
-		return null;
+		if (channel == null) return null;
+		return new AbstractMap.SimpleEntry<>(channel, channelMembers);
 	}
 
 	private static MethodDeclaration getInputMethod(TypeDeclaration type, ResourceNode resource, DataFlowModel model) {
diff --git a/AlgebraicDataflowArchitectureModel/src/algorithms/JerseyMethodBodyGenerator.java b/AlgebraicDataflowArchitectureModel/src/algorithms/JerseyMethodBodyGenerator.java
index c7e5ae5..89446db 100644
--- a/AlgebraicDataflowArchitectureModel/src/algorithms/JerseyMethodBodyGenerator.java
+++ b/AlgebraicDataflowArchitectureModel/src/algorithms/JerseyMethodBodyGenerator.java
@@ -220,23 +220,25 @@
 						getter.addStatement("return " + resource.getIdentifierTemplate().getResourceName() + ";");
 					}
 					// methods for input events
-					Map.Entry<DataflowChannelGenerator, ChannelMember> ioChannelAndMember = getIOChannelAndMember(resource, model);
-					if (ioChannelAndMember != null) {
-						ChannelMember out = ioChannelAndMember.getValue();
-						Term message = (Term) out.getStateTransition().getMessageExpression();
-						MethodDeclaration input = getMethod(type, message.getSymbol().getName());
-						if (input != null) {
-							Expression updateExp = ioChannelAndMember.getKey().deriveUpdateExpressionOf(out, JerseyCodeGenerator.pushAccessor);
-							String[] sideEffects = new String[] {""};
-							String newState = updateExp.toImplementation(sideEffects);
-							String updateStatement;
-							if (updateExp instanceof Term && ((Term) updateExp).getSymbol().isImplWithSideEffect()) {
-								updateStatement = sideEffects[0];								
-							} else {
-								updateStatement = sideEffects[0] + "this." + resourceName + " = " + newState + ";";
-							}
-							if (input.getBody() == null || !input.getBody().getStatements().contains(updateStatement)) {
-								input.addFirstStatement(updateStatement);
+					Map.Entry<DataflowChannelGenerator, Set<ChannelMember>> ioChannelAndMembers = getIOChannelAndMembers(resource, model);
+					if (ioChannelAndMembers != null) {
+						Set<ChannelMember> outs = ioChannelAndMembers.getValue();
+						for (ChannelMember out: outs) {
+							Term message = (Term) out.getStateTransition().getMessageExpression();
+							MethodDeclaration input = getMethod(type, message.getSymbol().getName());
+							if (input != null) {
+								Expression updateExp = ioChannelAndMembers.getKey().deriveUpdateExpressionOf(out, JerseyCodeGenerator.pushAccessor);
+								String[] sideEffects = new String[] {""};
+								String newState = updateExp.toImplementation(sideEffects);
+								String updateStatement;
+								if (updateExp instanceof Term && ((Term) updateExp).getSymbol().isImplWithSideEffect()) {
+									updateStatement = sideEffects[0];								
+								} else {
+									updateStatement = sideEffects[0] + "this." + resourceName + " = " + newState + ";";
+								}
+								if (input.getBody() == null || !input.getBody().getStatements().contains(updateStatement)) {
+									input.addFirstStatement(updateStatement);
+								}
 							}
 						}
 					}
@@ -380,20 +382,24 @@
 		return null;
 	}
 	
-	private static Map.Entry<DataflowChannelGenerator, ChannelMember> getIOChannelAndMember(ResourceNode resource, DataFlowModel model) {
+	private static Map.Entry<DataflowChannelGenerator, Set<ChannelMember>> getIOChannelAndMembers(ResourceNode resource, DataFlowModel model) {
+		Set<ChannelMember> channelMembers = new HashSet<>();
+		DataflowChannelGenerator channel = null;
 		for (ChannelGenerator c: model.getIOChannelGenerators()) {
-			DataflowChannelGenerator channel = (DataflowChannelGenerator) c;
+			DataflowChannelGenerator ch = (DataflowChannelGenerator) c;
 			// I/O channel
-			for (ChannelMember out: channel.getOutputChannelMembers()) {
+			for (ChannelMember out: ch.getOutputChannelMembers()) {
 				if (out.getIdentifierTemplate().equals(resource.getIdentifierTemplate())) {
 					if (out.getStateTransition().getMessageExpression() instanceof Term) {
 						// not an identity element
-						return new AbstractMap.SimpleEntry<>(channel, out);
+						channel = ch;
+						channelMembers.add(out);
 					}
 				}
 			}
 		}
-		return null;
+		if (channel == null) return null;
+		return new AbstractMap.SimpleEntry<>(channel, channelMembers);
 	}
 
 	private static MethodDeclaration getInputMethod(TypeDeclaration type, ResourceNode resource, DataFlowModel model) {