diff --git a/src/main/java/models/terms/Dependency.java b/src/main/java/models/terms/Dependency.java
index 3f02383..d382318 100644
--- a/src/main/java/models/terms/Dependency.java
+++ b/src/main/java/models/terms/Dependency.java
@@ -1,8 +1,8 @@
 package models.terms;
 
 import java.util.Arrays;
-import java.util.HashSet;
 import java.util.Set;
+import java.util.TreeSet;
 import java.util.stream.Collectors;
 
 import exceptions.SyntaxException;
@@ -13,26 +13,26 @@
 public class Dependency extends RDLTerm{
 	
 	private RDLTerm dependingTerm;
-	private Set<EvaluatableTerm> dependedTerms;
+	private TreeSet<EvaluatableTerm> dependedTerms;
 	
 	public Dependency(RDLTerm dependingTerm, Set<EvaluatableTerm> dependedTerms) {
 		super(new Symbol(":", dependedTerms.size() + 1), dependedTerms.iterator().next().getOrder(), dependingTerm.getSize() + dependedTerms.stream().mapToInt(v -> v.size).sum());
 		this.dependingTerm = dependingTerm;
-		this.dependedTerms = dependedTerms;
+		this.dependedTerms = new TreeSet<>(dependedTerms);
 		this.addChild(dependingTerm);
-		if (dependingTerm.getOrder() > getOrder() - 1) {
-			throw new SyntaxException("dependingTerm's order must be less than" + (getOrder() + 1) + ", but " + dependingTerm + "'s order is " + dependingTerm.getOrder());
+		if (dependingTerm.getTermOrder() > getOrder()) {
+			throw new SyntaxException("dependingTerm's order must be less than " + (getOrder() + 1) + ", but " + dependingTerm + "'s order is " + dependingTerm.getOrder());
 		}
 		for (EvaluatableTerm dependedTerm: dependedTerms) {
 			this.addChild(dependedTerm);
-			if (dependedTerm.getOrder() != getOrder()) {
+			if (dependedTerm.getTermOrder() != getOrder()) {
 				throw new SyntaxException(dependedTerm + " order is not " + getOrder());
 			}
 		}
 	}
 	
 	public Dependency(RDLTerm dependingTerm, EvaluatableTerm ...dependedTerms) {
-		this(dependingTerm, new HashSet<>(Arrays.asList(dependedTerms)));
+		this(dependingTerm, new TreeSet<>(Arrays.asList(dependedTerms)));
 	}
 	
 	@Override
@@ -49,7 +49,7 @@
 		StringBuilder sb = new StringBuilder();
 		sb.append(dependingTerm.toTermString());
 		sb.append(" : ");
-		sb.append(dependedTerms.toString());
+		sb.append(dependedTerms.stream().map(RDLTerm::toString).collect(Collectors.joining(", ")));
 		return sb.toString();
 	}
 	
@@ -84,7 +84,7 @@
 	
 	@Override
 	public Object clone() {
-		return new Dependency((RDLTerm) dependingTerm.clone(), new HashSet<>(dependedTerms));
+		return new Dependency((RDLTerm) dependingTerm.clone(), new TreeSet<>(dependedTerms));
 	}
 
 }