diff --git a/src/mhtree/Histogram.java b/src/mhtree/Histogram.java
index 3f96f9daff19736b283b0b4a9ecc57b6a20ff521..470c6f681109ba1e129afb7ca38724f03c5da136 100644
--- a/src/mhtree/Histogram.java
+++ b/src/mhtree/Histogram.java
@@ -5,7 +5,6 @@ import messif.objects.LocalAbstractObject;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
-import java.util.Set;
 
 public class Histogram {
     private final HashMap<Integer, HashMap<Long, Integer>> levelToHullsCoveredToObjectCount = new HashMap<>();
@@ -17,7 +16,7 @@ public class Histogram {
         Histogram histogram = new Histogram();
 
         for (int level = 1; level <= x.getHeight() + 1; level++) {
-            Set<Node> levelNodes = x.getNodesOnLevel(level);
+            List<Node> levelNodes = x.getNodesOnLevel(level);
 
             for (LocalAbstractObject object : x.getObjects()) {
                 long coveredObjectCount = levelNodes.stream()
diff --git a/src/mhtree/MHTree.java b/src/mhtree/MHTree.java
index ee6dd22cca37b0db22a07b281406f9fd5aa4f339..5bf4ae3d7d7a9fa1bbb8dd720cef3d8807959c7b 100644
--- a/src/mhtree/MHTree.java
+++ b/src/mhtree/MHTree.java
@@ -35,11 +35,11 @@ public class MHTree extends Algorithm implements Serializable {
 
     @AlgorithmConstructor(description = "MH-Tree", arguments = {
             "list of objects",
-            "number of objects in leaf node",
+            "number of objects in a leaf node",
             "arity",
-            "number of threads used in precomputing distances",
             "insert type",
-            "distance measure",
+            "object to node distance type",
+            "node to node distance type",
             "storage class for buckets",
             "storage class parameters"
     })
@@ -130,7 +130,7 @@ public class MHTree extends Algorithm implements Serializable {
 
         System.out.println("Number of hull objects in each level:");
         for (int level = 1; level <= root.getHeight() + 1; level++) {
-            Set<Node> levelNodes = root.getNodesOnLevel(level);
+            List<Node> levelNodes = root.getNodesOnLevel(level);
 
             System.out.println("- Level " + level + " -> " + levelNodes.stream().mapToInt(n -> n.getHullObjects().size()).summaryStatistics());
         }