diff --git a/src/main/java/org/gcube/informationsystem/utils/documentation/generator/TreeGenerator.java b/src/main/java/org/gcube/informationsystem/utils/documentation/generator/TreeGenerator.java
index 40e8ebe..a50be7c 100644
--- a/src/main/java/org/gcube/informationsystem/utils/documentation/generator/TreeGenerator.java
+++ b/src/main/java/org/gcube/informationsystem/utils/documentation/generator/TreeGenerator.java
@@ -15,10 +15,10 @@ import org.gcube.informationsystem.model.reference.properties.PropagationConstra
 import org.gcube.informationsystem.model.reference.properties.Property;
 import org.gcube.informationsystem.types.TypeMapper;
 import org.gcube.informationsystem.types.reference.Type;
-import org.gcube.informationsystem.utils.documentation.knowledge.Node;
-import org.gcube.informationsystem.utils.documentation.knowledge.NodeElaborator;
-import org.gcube.informationsystem.utils.documentation.knowledge.Tree;
 import org.gcube.informationsystem.utils.documentation.model.DocumentationGenerator;
+import org.gcube.informationsystem.utils.knowledge.Node;
+import org.gcube.informationsystem.utils.knowledge.NodeElaborator;
+import org.gcube.informationsystem.utils.knowledge.Tree;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
diff --git a/src/main/java/org/gcube/informationsystem/utils/documentation/knowledge/Node.java b/src/main/java/org/gcube/informationsystem/utils/documentation/knowledge/Node.java
deleted file mode 100644
index d796538..0000000
--- a/src/main/java/org/gcube/informationsystem/utils/documentation/knowledge/Node.java
+++ /dev/null
@@ -1,111 +0,0 @@
-package org.gcube.informationsystem.utils.documentation.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/documentation/knowledge/NodeElaborator.java b/src/main/java/org/gcube/informationsystem/utils/documentation/knowledge/NodeElaborator.java
deleted file mode 100644
index 7e62057..0000000
--- a/src/main/java/org/gcube/informationsystem/utils/documentation/knowledge/NodeElaborator.java
+++ /dev/null
@@ -1,10 +0,0 @@
-package org.gcube.informationsystem.utils.documentation.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/documentation/knowledge/Tree.java b/src/main/java/org/gcube/informationsystem/utils/documentation/knowledge/Tree.java
deleted file mode 100644
index 04d13e2..0000000
--- a/src/main/java/org/gcube/informationsystem/utils/documentation/knowledge/Tree.java
+++ /dev/null
@@ -1,79 +0,0 @@
-package org.gcube.informationsystem.utils.documentation.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/documentation/knowledge/UsageKnowledge.java b/src/main/java/org/gcube/informationsystem/utils/documentation/knowledge/UsageKnowledge.java
deleted file mode 100644
index 0ef1806..0000000
--- a/src/main/java/org/gcube/informationsystem/utils/documentation/knowledge/UsageKnowledge.java
+++ /dev/null
@@ -1,73 +0,0 @@
-package org.gcube.informationsystem.utils.documentation.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;
-	}
-	
-}
diff --git a/src/main/java/org/gcube/informationsystem/utils/documentation/model/entities/FacetDocumentationGenerator.java b/src/main/java/org/gcube/informationsystem/utils/documentation/model/entities/FacetDocumentationGenerator.java
index 2e4faca..689291f 100644
--- a/src/main/java/org/gcube/informationsystem/utils/documentation/model/entities/FacetDocumentationGenerator.java
+++ b/src/main/java/org/gcube/informationsystem/utils/documentation/model/entities/FacetDocumentationGenerator.java
@@ -6,8 +6,8 @@ import org.gcube.informationsystem.base.reference.AccessType;
 import org.gcube.informationsystem.types.reference.Type;
 import org.gcube.informationsystem.types.reference.properties.LinkedEntity;
 import org.gcube.informationsystem.types.reference.properties.PropertyDefinition;
-import org.gcube.informationsystem.utils.documentation.knowledge.UsageKnowledge;
 import org.gcube.informationsystem.utils.documentation.rst.table.Table;
+import org.gcube.informationsystem.utils.knowledge.UsageKnowledge;
 
 /**
  * @author Luca Frosini (ISTI - CNR)
diff --git a/src/main/java/org/gcube/informationsystem/utils/documentation/model/entities/ResourceDocumentationGenerator.java b/src/main/java/org/gcube/informationsystem/utils/documentation/model/entities/ResourceDocumentationGenerator.java
index b0f3ba0..37220d2 100644
--- a/src/main/java/org/gcube/informationsystem/utils/documentation/model/entities/ResourceDocumentationGenerator.java
+++ b/src/main/java/org/gcube/informationsystem/utils/documentation/model/entities/ResourceDocumentationGenerator.java
@@ -6,8 +6,8 @@ import org.gcube.informationsystem.base.reference.AccessType;
 import org.gcube.informationsystem.types.reference.Type;
 import org.gcube.informationsystem.types.reference.entities.ResourceType;
 import org.gcube.informationsystem.types.reference.properties.LinkedEntity;
-import org.gcube.informationsystem.utils.documentation.knowledge.UsageKnowledge;
 import org.gcube.informationsystem.utils.documentation.rst.table.Table;
+import org.gcube.informationsystem.utils.knowledge.UsageKnowledge;
 
 /**
  * @author Luca Frosini (ISTI - CNR)
diff --git a/src/main/java/org/gcube/informationsystem/utils/documentation/model/relations/ConsistsOfDocumentationGenerator.java b/src/main/java/org/gcube/informationsystem/utils/documentation/model/relations/ConsistsOfDocumentationGenerator.java
index d8cd1dc..fe3455e 100644
--- a/src/main/java/org/gcube/informationsystem/utils/documentation/model/relations/ConsistsOfDocumentationGenerator.java
+++ b/src/main/java/org/gcube/informationsystem/utils/documentation/model/relations/ConsistsOfDocumentationGenerator.java
@@ -5,8 +5,8 @@ import java.util.Set;
 import org.gcube.informationsystem.base.reference.AccessType;
 import org.gcube.informationsystem.types.reference.Type;
 import org.gcube.informationsystem.types.reference.properties.LinkedEntity;
-import org.gcube.informationsystem.utils.documentation.knowledge.UsageKnowledge;
 import org.gcube.informationsystem.utils.documentation.rst.table.Table;
+import org.gcube.informationsystem.utils.knowledge.UsageKnowledge;
 
 /**
  * @author Luca Frosini (ISTI - CNR)
diff --git a/src/main/java/org/gcube/informationsystem/utils/documentation/model/relations/IsRelatedToDocumentationGenerator.java b/src/main/java/org/gcube/informationsystem/utils/documentation/model/relations/IsRelatedToDocumentationGenerator.java
index d9c6603..e21e1da 100644
--- a/src/main/java/org/gcube/informationsystem/utils/documentation/model/relations/IsRelatedToDocumentationGenerator.java
+++ b/src/main/java/org/gcube/informationsystem/utils/documentation/model/relations/IsRelatedToDocumentationGenerator.java
@@ -5,8 +5,8 @@ import java.util.Set;
 import org.gcube.informationsystem.base.reference.AccessType;
 import org.gcube.informationsystem.types.reference.Type;
 import org.gcube.informationsystem.types.reference.properties.LinkedEntity;
-import org.gcube.informationsystem.utils.documentation.knowledge.UsageKnowledge;
 import org.gcube.informationsystem.utils.documentation.rst.table.Table;
+import org.gcube.informationsystem.utils.knowledge.UsageKnowledge;
 
 /**
  * @author Luca Frosini (ISTI - CNR)