diff --git a/src/main/java/org/gcube/informationsystem/utils/knowledge/Node.java b/src/main/java/org/gcube/informationsystem/utils/knowledge/Node.java
new file mode 100644
index 0000000..4e5707e
--- /dev/null
+++ b/src/main/java/org/gcube/informationsystem/utils/knowledge/Node.java
@@ -0,0 +1,111 @@
+package org.gcube.informationsystem.utils.knowledge;
+
+import java.util.Set;
+import java.util.TreeSet;
+
+import org.gcube.informationsystem.types.reference.Type;
+
+/**
+ * @author Luca Frosini (ISTI - CNR)
+ */
+public class Node implements Comparable<Node> {
+
+	public static String INDENTATION = "\t";
+	
+	private Type type;
+	
+	private Tree tree;
+	
+	private Node parent;
+	private Set<Node> children;
+	
+	public Node(Type type) {
+		this.type = type;
+		this.children = new TreeSet<Node>();
+	}
+	
+	public Tree getTree() {
+		return tree;
+	}
+
+	private void setTree(Tree tree) {
+		this.tree = tree;
+	}
+	
+	public Type getType() {
+		return type;
+	}
+	
+	public Node getParent() {
+		return parent;
+	}
+	
+	public Node setParent(Node parent) {
+		this.parent = parent;
+		return this;
+	}
+
+	public Node addChild(Node child) {
+		children.add(child);
+		child.setParent(this);
+		child.setTree(tree);
+		return this;
+	}
+
+	public Set<Node> getChildrenNodes() {
+		return children;
+	}
+	
+	public Set<Type> getChildren() {
+		Set<Type> sortedChildren = new TreeSet<>();
+		for (Node treeNode : children) {
+			sortedChildren.add(treeNode.type);
+		}
+		return sortedChildren;
+	}
+
+	@Override
+	public String toString() {
+		return createTree(0).toString();
+	}
+
+	private StringBuffer createTree(int level) {
+		StringBuffer stringBuffer = new StringBuffer();
+		for (int i = 0; i < level; ++i) {
+			stringBuffer.append(Node.INDENTATION);
+		}
+		stringBuffer.append(type.getName());
+		for (Node child : children) {
+			stringBuffer.append("\n");
+			stringBuffer.append(child.createTree(level+1));
+		}
+		return stringBuffer;
+	}
+
+	@Override
+	public int compareTo(Node other) {
+		if (this == other) {
+			return 0;
+		}
+		if (other == null) {
+			return -1;
+		}
+		if (getClass() != other.getClass()) {
+			return -1;
+		}
+		
+		return type.getName().compareTo(other.type.getName());
+	}
+	
+	
+	public void elaborate(NodeElaborator nodeElaborator) throws Exception {
+		elaborate(nodeElaborator, 0);
+	}
+	
+	protected void elaborate(NodeElaborator nodeElaborator, int level) throws Exception {
+		nodeElaborator.elaborate(this, level);
+		for (Node child : children) {
+			child.elaborate(nodeElaborator, level+1);
+		}
+	}
+}
diff --git a/src/main/java/org/gcube/informationsystem/utils/knowledge/NodeElaborator.java b/src/main/java/org/gcube/informationsystem/utils/knowledge/NodeElaborator.java
new file mode 100644
index 0000000..7c230b1
--- /dev/null
+++ b/src/main/java/org/gcube/informationsystem/utils/knowledge/NodeElaborator.java
@@ -0,0 +1,10 @@
+package org.gcube.informationsystem.utils.knowledge;
+
+/**
+ * @author Luca Frosini (ISTI - CNR)
+ */
+public interface NodeElaborator {
+
+	public void elaborate(Node node, int level) throws Exception;
+
+}
diff --git a/src/main/java/org/gcube/informationsystem/utils/knowledge/Tree.java b/src/main/java/org/gcube/informationsystem/utils/knowledge/Tree.java
new file mode 100644
index 0000000..d89e045
--- /dev/null
+++ b/src/main/java/org/gcube/informationsystem/utils/knowledge/Tree.java
@@ -0,0 +1,79 @@
+package org.gcube.informationsystem.utils.knowledge;
+
+import java.util.HashMap;
+import java.util.Set;
+
+import org.gcube.informationsystem.base.reference.AccessType;
+import org.gcube.informationsystem.types.reference.Type;
+import org.gcube.informationsystem.types.reference.entities.ResourceType;
+
+/**
+ * @author Luca Frosini (ISTI - CNR)
+ */
+public class Tree {
+
+	private Node root;
+	
+	private boolean allowMultipleInheritance;
+	private HashMap<String, Node> locate = new HashMap<String, Node>();
+	
+	
+	public Tree(Type head) {
+		this.root = new Node(head);
+		this.locate.put(head.getName(), root);
+		this.allowMultipleInheritance = false;
+	}
+	
+	public void setAllowMultipleInheritance(boolean allowMultipleInheritance) {
+		this.allowMultipleInheritance = allowMultipleInheritance;
+	}
+	
+	public void createUsageKnowledge(Type type) {
+		if(type.getAccessType() != AccessType.RESOURCE) {
+			return;
+		}
+		ResourceType rt = (ResourceType) type;
+		UsageKnowledge fk = UsageKnowledge.getFacetKnowledge();
+		fk.addAll(rt.getFacets());
+		UsageKnowledge rk = UsageKnowledge.getResourceKnowledge();
+		rk.addAll(rt.getResources()); 
+	}
+	
+	public void addNode(Type type) {
+		createUsageKnowledge(type);
+		
+		if(root.getType().getName().compareTo(type.getName())==0) {
+			// Root has been already added
+			return;
+		}
+		
+		Set<String> superClasses = type.getSuperClasses();
+		
+		String name = type.getName();
+		for(String superClass : superClasses) {
+			Node parent = locate.get(superClass);
+			if(parent==null) {
+				throw new RuntimeException("I can find parent Node for " + name + ". Missing parent is " + superClass);
+			}
+			Node node = new Node(type);
+			parent.addChild(node);
+			locate.put(name, node);
+			if(!allowMultipleInheritance) {
+				return;
+			}
+		}
+	}
+
+	public Node getRoot() {
+		return root;
+	}
+
+	@Override
+	public String toString() {
+		return root.toString();
+	}
+
+	public void elaborate(NodeElaborator nodeElaborator) throws Exception {
+		root.elaborate(nodeElaborator);
+	}
+}
\ No newline at end of file
diff --git a/src/main/java/org/gcube/informationsystem/utils/knowledge/UsageKnowledge.java b/src/main/java/org/gcube/informationsystem/utils/knowledge/UsageKnowledge.java
new file mode 100644
index 0000000..091ceb7
--- /dev/null
+++ b/src/main/java/org/gcube/informationsystem/utils/knowledge/UsageKnowledge.java
@@ -0,0 +1,73 @@
+package org.gcube.informationsystem.utils.knowledge;
+
+import java.util.Collection;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeSet;
+
+import org.gcube.informationsystem.types.reference.properties.LinkedEntity;
+
+/**
+ * @author Luca Frosini (ISTI - CNR)
+ */
+public class UsageKnowledge {
+	
+	private static UsageKnowledge facetKnowledge;
+	private static UsageKnowledge resourceKnowledge;
+	
+	public static UsageKnowledge getFacetKnowledge() {
+		if(UsageKnowledge.facetKnowledge==null) {
+			UsageKnowledge.facetKnowledge = new UsageKnowledge();
+		}
+		return UsageKnowledge.facetKnowledge;
+	}
+	
+	public static UsageKnowledge getResourceKnowledge() {
+		if(UsageKnowledge.resourceKnowledge==null) {
+			UsageKnowledge.resourceKnowledge = new UsageKnowledge();
+		}
+		return UsageKnowledge.resourceKnowledge;
+	}
+	
+	
+	protected Map<String, Set<LinkedEntity>> map;
+	
+	private UsageKnowledge(){
+		this.map = new LinkedHashMap<>();
+	}
+	
+	protected void add(String typeName, LinkedEntity linkedEntity) {
+		Set<LinkedEntity> list = map.get(typeName);
+		if(list==null) {
+			list = new TreeSet<>();
+			map.put(typeName, list);
+		}
+		list.add(linkedEntity);
+	}
+	
+	public void add(LinkedEntity linkedEntity) {
+		if(linkedEntity!=null) {
+			String source = linkedEntity.getSource();
+			add(source, linkedEntity);
+			String relation = linkedEntity.getRelation();
+			add(relation, linkedEntity);
+			String target = linkedEntity.getTarget();
+			add(target, linkedEntity);
+		}
+	}
+	
+	public void addAll(Collection<LinkedEntity> linkedEntities) {
+		if(linkedEntities!=null) {
+			for(LinkedEntity le : linkedEntities) {
+				add(le);
+			}
+		}
+	}
+	
+	public Set<LinkedEntity> getUsage(String typeName){
+		Set<LinkedEntity> list = map.get(typeName);
+		return list;
+	}
+	
+}