diff --git a/src/models/DependencyTerm.java b/src/models/DependencyTerm.java
index 87a35a0..3a437df 100644
--- a/src/models/DependencyTerm.java
+++ b/src/models/DependencyTerm.java
@@ -6,20 +6,22 @@
 @Getter
 public class DependencyTerm extends EvaluatableTerm{
 
-	private Dependency dependency;
+	private EvaluatableTerm dependingTerm;
+	private ResourceVariable dependedVariable;
 	private EvaluatableTerm argumentTerm;
 	
 	public DependencyTerm(int order) {
 		super(new Symbol(":", 3), order);
 	}
 	
-	public DependencyTerm(Dependency dependency, EvaluatableTerm argumentTerm) {
-		super(new Symbol(":", 3), dependency.getDependedVariable().getOrder() - 1);
-		this.dependency = dependency;
+	public DependencyTerm(EvaluatableTerm dependingTerm, ResourceVariable dependedVariable, EvaluatableTerm argumentTerm) {
+		super(new Symbol(":", 3), dependedVariable.getOrder() == argumentTerm.getOrder() ? dependedVariable.getOrder() : dependedVariable.getOrder() - 1);
+		this.dependingTerm = dependingTerm;
+		this.dependedVariable = dependedVariable;
 		this.argumentTerm = argumentTerm;
-		this.addChild(dependency.getDependingTerm());
-		this.addChild(dependency.getDependedVariable());
-		this.addChild(argumentTerm);
+		addChild(dependingTerm);
+		addChild(dependedVariable);
+		addChild(argumentTerm);
 	}
 	
 	@Override
@@ -35,52 +37,38 @@
 	}
 	
 	@Override
-	public int getOrder() {
-		ResourceVariable variable = dependency.getDependedVariable();
-		if(variable.getOrder() == argumentTerm.getOrder()) {
-			return variable.getOrder();
-		} else {
-			return variable.getOrder() - 1;
-		}
-	}
-
-	@Override
 	public void selfLinearRightNormalize() {
-		EvaluatableTerm term = (EvaluatableTerm) dependency.getDependingTerm(); //depending term. a of [a : b -> c] 
-		if(term instanceof ResourceVariable || term instanceof SetEvaluatableTerm) {
+		if(dependingTerm instanceof ResourceVariable || dependingTerm instanceof SetEvaluatableTerm) {
 			argumentTerm.selfLinearRightNormalize();
 			return;
 		}
-		DependencyTerm dependencyTerm = (DependencyTerm) term;
+		DependencyTerm dependencyTerm = (DependencyTerm) dependingTerm;
 		if(! dependencyTerm.isLinearRightNormal()) {
 			dependencyTerm.selfLinearRightNormalize();
 		}
 		if(! isLinearRightNormal()) {
-			Dependency childDependency = dependencyTerm.getDependency();
 			EvaluatableTerm childArgumentTerm = dependencyTerm.getArgumentTerm();
-			Dependency nextDependency = new Dependency(childArgumentTerm, dependency.getDependedVariable());
-			DependencyTerm nextDependencyTerm = new DependencyTerm(nextDependency, argumentTerm);
+			DependencyTerm nextDependencyTerm = new DependencyTerm(childArgumentTerm, dependedVariable, argumentTerm);
+			this.dependingTerm = dependencyTerm.getDependingTerm();
+			this.dependedVariable = dependencyTerm.getDependedVariable();
 			this.argumentTerm = nextDependencyTerm;
-			this.dependency = childDependency;
 			this.setChild(3, nextDependencyTerm);
-			this.setChild(0, childDependency.getChild(0));
-			this.setChild(1, childDependency.getChild(1));
+			this.setChild(0, dependencyTerm.getDependingTerm());
+			this.setChild(1, dependencyTerm.getDependedVariable());
 		}
 		argumentTerm.selfLinearRightNormalize();
 		
 	}
 	
 	private boolean isLinearRightNormal(int depth) {
-		EvaluatableTerm term = (EvaluatableTerm) dependency.getDependingTerm(); //depending term. a of [a : b -> c] 
-		ResourceVariable variable = dependency.getDependedVariable();
-		if(term instanceof ResourceVariable || term instanceof SetEvaluatableTerm) {
-			return term.getOrder() == variable.getOrder();
+		if(dependingTerm instanceof ResourceVariable || dependingTerm instanceof SetEvaluatableTerm) {
+			return dependingTerm.getOrder() == dependedVariable.getOrder();
 		}
-		DependencyTerm dependencyTerm = (DependencyTerm) term;
+		DependencyTerm dependencyTerm = (DependencyTerm) dependingTerm;
 		if(
 				dependencyTerm.isLinearRightNormal(depth + 1) && 
-				dependencyTerm.getDependency().getDependedVariable().getOrder() - 1 == variable.getOrder() && 
-				dependencyTerm.getOrder() == variable.getOrder() &&
+				dependencyTerm.getDependedVariable().getOrder() - 1 == dependedVariable.getOrder() && 
+				dependencyTerm.getOrder() == dependedVariable.getOrder() &&
 				argumentTerm.getOrder() <= dependencyTerm.getOrder() &&
 				depth == 0
 		) {
@@ -88,8 +76,8 @@
 		}
 		if(
 				dependencyTerm.isLinearRightNormal(depth + 1) && 
-				dependencyTerm.getDependency().getDependedVariable().getOrder() - 1 == variable.getOrder() && 
-				dependencyTerm.getOrder() == variable.getOrder() &&
+				dependencyTerm.getDependedVariable().getOrder() - 1 == dependedVariable.getOrder() && 
+				dependencyTerm.getOrder() == dependedVariable.getOrder() &&
 				argumentTerm.getOrder() < dependencyTerm.getOrder()
 		) {
 			return true;
@@ -102,9 +90,9 @@
 	public String toString() {
 		StringBuilder sb = new StringBuilder();
 		sb.append('[');
-		sb.append(dependency.getDependingTerm().toString());
+		sb.append(getDependingTerm().toString());
 		sb.append(" : ");
-		sb.append(dependency.getDependedVariable().toString());
+		sb.append(getDependedVariable().toString());
 		sb.append(" -> ");
 		sb.append(argumentTerm.toString());
 		sb.append(']');
@@ -115,9 +103,9 @@
 	public String toStringWithOrder() {
 		StringBuilder sb = new StringBuilder();
 		sb.append('[');
-		sb.append(dependency.getDependingTerm().toStringWithOrder());
+		sb.append(getDependingTerm().toStringWithOrder());
 		sb.append(" : ");
-		sb.append(dependency.getDependedVariable().toStringWithOrder());
+		sb.append(getDependedVariable().toStringWithOrder());
 		sb.append(" -> ");
 		sb.append(argumentTerm.toStringWithOrder());
 		sb.append(']');
@@ -133,7 +121,9 @@
 			return false;
 		}
 		DependencyTerm term = (DependencyTerm) another;
-		return term.getDependency().equals(dependency) && term.getArgumentTerm().equals(argumentTerm);
+		return dependingTerm.equals(term.getDependingTerm()) && 
+				dependedVariable.equals(term.getDependedVariable()) && 
+				argumentTerm.equals(term.getArgumentTerm());
 	}
 
 	@Override
@@ -144,7 +134,8 @@
 	@Override
 	public Object clone() {
 		return new DependencyTerm(
-				(Dependency) dependency.clone(),
+				(EvaluatableTerm) dependingTerm.clone(),
+				(ResourceVariable) dependedVariable.clone(),
 				(EvaluatableTerm) argumentTerm.clone() 
 		);
 	}
diff --git a/src/models/EvaluatableTerm.java b/src/models/EvaluatableTerm.java
index 5a80673..24d7e9e 100644
--- a/src/models/EvaluatableTerm.java
+++ b/src/models/EvaluatableTerm.java
@@ -1,5 +1,6 @@
 package models;
 
+import exceptions.IllegalTypeException;
 import models.algebra.Symbol;
 import models.algebra.Type;
 
@@ -19,31 +20,39 @@
 	}
 	
 	public static DependencyTerm of(EvaluatableTerm term, ResourceVariable variable, EvaluatableTerm valueTerm) {
-		return new DependencyTerm(new Dependency(term, variable), valueTerm);
+		return new DependencyTerm(term, variable, valueTerm);
 	}
 	
 	public static EvaluatableTerm of(EvaluatableTerm term, ResourceVariable variable, EvaluatableTerm valueTerm, int order) {
 		if(variable.getOrder() == valueTerm.getOrder() && variable.getOrder() == order) {
-			return new DependencyTerm(new Dependency(term, variable), valueTerm);
+			return new DependencyTerm(term, variable, valueTerm);
 		} else if(variable.getOrder() -1 == order) {
-			return new DependencyTerm(new Dependency(term, variable), valueTerm);
+			return new DependencyTerm(term, variable, valueTerm);
 		} else {
-			return new SetEvaluatableTerm(new DependencyTerm(new Dependency(term, variable), valueTerm), order);
+			return new SetEvaluatableTerm(new DependencyTerm(term, variable, valueTerm), order);
 		}
 	}
 	
 	public static DependencyTerm of(Dependency dependency, EvaluatableTerm argumentTerm) {
-		return new DependencyTerm(dependency, argumentTerm);
+		RDLTerm term = dependency.getDependingTerm();
+		if(! (term instanceof EvaluatableTerm)) {
+			throw new IllegalTypeException();
+		}
+		return new DependencyTerm((EvaluatableTerm) term, dependency.getDependedVariable(), argumentTerm);
 	}
 	
 	public static EvaluatableTerm of(Dependency dependency, EvaluatableTerm argumentTerm, int order) {
+		RDLTerm term = dependency.getDependingTerm();
+		if(! (term instanceof EvaluatableTerm)) {
+			throw new IllegalTypeException();
+		}
 		ResourceVariable variable = dependency.getDependedVariable();
 		if(variable.getOrder() == argumentTerm.getOrder() && variable.getOrder() == order) {
-			return new DependencyTerm(dependency, argumentTerm);
+			return new DependencyTerm((EvaluatableTerm) term, variable, argumentTerm);
 		} else if(variable.getOrder() - 1 == order) {
-			return new DependencyTerm(dependency, argumentTerm);
+			return new DependencyTerm((EvaluatableTerm) term, variable, argumentTerm);
 		} else {
-			return new SetEvaluatableTerm(new DependencyTerm(dependency, argumentTerm), order); 
+			return new SetEvaluatableTerm(new DependencyTerm((EvaluatableTerm) term, variable, argumentTerm), order); 
 		}
 	}