diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java b/src/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java
index ddac6b91..1ad6f28b 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java
@@ -41,11 +41,11 @@ public class FiniteClosure implements IFiniteClosure {
 			Node<UnifyType> parentNode = inheritanceGraph.get(pair.getRhsType());
 			
 			// Add edge
-			parentNode.AddDescendant(childNode);
+			parentNode.addDescendant(childNode);
 			
 			// Add edges to build the transitive closure
-			parentNode.getPredecessors().stream().forEach(x -> x.AddDescendant(childNode));
-			childNode.getDescendants().stream().forEach(x -> x.AddPredecessor(parentNode));
+			parentNode.getPredecessors().stream().forEach(x -> x.addDescendant(childNode));
+			childNode.getDescendants().stream().forEach(x -> x.addPredecessor(parentNode));
 		}
 		
 		// Build the alternative representation with strings as keys
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/FunNType.java b/src/de/dhbwstuttgart/typeinference/unify/model/FunNType.java
index 3363be75..94ac1cf8 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/FunNType.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/FunNType.java
@@ -4,35 +4,45 @@ import java.util.Set;
 
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
 
+/**
+ * A real function type in java.
+ * @author Florian Steurer
+ */
 public class FunNType extends UnifyType {
 
+	/**
+	 * Creates a FunN-Type with the specified TypeParameters.
+	 */
 	protected FunNType(TypeParams p) {
 		super("FuN", p);
 	}
 
-	public static FunNType getFunNType(TypeParams tp) {
-		if(!validateTypeParams(tp))
-			throw new IllegalArgumentException("Invalid TypeParams for a FunNType: " + tp);
+	/**
+	 * Creates a new FunNType.
+	 * @param tp The parameters of the type.
+	 * @return A FunNType.
+	 * @throws IllegalArgumentException is thrown when there are to few type parameters or there are wildcard-types.
+	 */
+	public static FunNType getFunNType(TypeParams tp) throws IllegalArgumentException {
+		if(tp.size() == 0)
+			throw new IllegalArgumentException("FunNTypes need at least one type parameter");
+		for(UnifyType t : tp)
+			if(t instanceof WildcardType)
+				throw new IllegalArgumentException("Invalid TypeParams for a FunNType: " + tp);
 		return new FunNType(tp);
 	}
 	
-	private static boolean validateTypeParams(TypeParams tp) {
-		if(tp.size() == 0)
-			return false;
-		for(UnifyType t : tp)
-			if(t instanceof WildcardType)
-				return false;
-		return true;
+	/**
+	 * Returns the degree of the function type, e.g. 2 for FunN<Integer, Integer, Integer>.
+	 */
+	public int getN() {
+		return typeParams.size()-1;
 	}
 	
 	@Override
 	public UnifyType setTypeParams(TypeParams newTp) {
 		return getFunNType(newTp);
 	}
-
-	public int getN() {
-		return typeParams.size()-1;
-	}
 	
 	@Override
 	Set<UnifyType> smArg(IFiniteClosure fc) {
@@ -46,13 +56,14 @@ public class FunNType extends UnifyType {
 	
 	@Override
 	UnifyType apply(Unifier unif) {
-		// TODO Auto-generated method stub
-		return null;
+		// TODO this bypasses the validation of the type parameters.
+		// Wildcard types can be unified into FunNTypes.
+		return new FunNType(typeParams.apply(unif));
 	}
 
 	@Override
 	public int hashCode() {
-		return 31 + typeParams.hashCode();
+		return 181 + typeParams.hashCode();
 	}
 	
 	@Override
diff --git a/src/de/dhbwstuttgart/typeinference/unify/model/Node.java b/src/de/dhbwstuttgart/typeinference/unify/model/Node.java
index d338d16b..d24b6825 100644
--- a/src/de/dhbwstuttgart/typeinference/unify/model/Node.java
+++ b/src/de/dhbwstuttgart/typeinference/unify/model/Node.java
@@ -4,48 +4,90 @@ import java.util.HashSet;
 import java.util.Set;
 import java.util.stream.Collectors;
 
+/**
+ * A node of a directed graph.
+ * @author Florian Steurer
+ *
+ * @param <T> The type of the content of the node.
+ */
 class Node<T> {
+	
+	/**
+	 * The content of the node.
+	 */
 	private T content;
 	
+	/**
+	 * The set of predecessors
+	 */
 	private HashSet<Node<T>> predecessors = new HashSet<>();
+	
+	/**
+	 * The set of descendants
+	 */
 	private HashSet<Node<T>> descendants = new HashSet<>();
 	
+	/**
+	 * Creates a node containing the specified content.
+	 */
 	public Node(T content) {
 		this.content = content;
 	}
 	
-	public void AddDescendant(Node<T> descendant) {
+	/**
+	 * Adds a directed edge from this node to the descendant (this -> descendant)
+	 */
+	public void addDescendant(Node<T> descendant) {
 		if(descendants.contains(descendant))
 			return;
 		
 		descendants.add(descendant);
-		descendant.AddPredecessor(this);
+		descendant.addPredecessor(this);
 	}
 	
-	public void AddPredecessor(Node<T> predecessor) {
+	/**
+	 * Adds a directed edge from the predecessor to this node (predecessor -> this)
+	 */
+	public void addPredecessor(Node<T> predecessor) {
 		if(predecessors.contains(predecessor))
 			return;
 		
 		predecessors.add(predecessor);
-		predecessor.AddDescendant(this);
+		predecessor.addDescendant(this);
 	}
 	
+	/**
+	 * The content of this node.
+	 */
 	public T getContent() {
 		return content;
 	}
 	
+	/**
+	 * Returns all predecessors (nodes that have a directed edge to this node)
+	 */
 	public Set<Node<T>> getPredecessors() {
 		return predecessors;
 	}
 	
+	/**
+	 * Returns all descendants. All nodes M, where there is a edge from this node to the node M.
+	 * @return
+	 */
 	public Set<Node<T>> getDescendants() {
 		return descendants;
 	}
 	
+	/**
+	 * Retrieves the content of all descendants.
+	 */
 	public Set<T> getContentOfDescendants() {
 		return descendants.stream().map(x -> x.getContent()).collect(Collectors.toSet());
 	}
 	
+	/**
+	 * Retrieves the content of all predecessors.
+	 */
 	public Set<T> getContentOfPredecessors() {
 		return predecessors.stream().map(x -> x.getContent()).collect(Collectors.toSet());
 	}