diff --git a/4. labor/BeerRegister/src/beerregister/BeerRegister.java b/4. labor/BeerRegister/src/beerregister/BeerRegister.java
index 47930169839434b30505fde65cbbf5b4ef069a7b..db680fb731559667f3f6f8406b6b4c96d2394548 100644
--- a/4. labor/BeerRegister/src/beerregister/BeerRegister.java	
+++ b/4. labor/BeerRegister/src/beerregister/BeerRegister.java	
@@ -9,6 +9,7 @@ import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.Comparator;
 
 public class BeerRegister {
 	public static void main(String[] args) throws IOException, ClassNotFoundException 
@@ -24,7 +25,25 @@ public class BeerRegister {
 					storage.add(new Beer(cmd[1], cmd[2], Double.parseDouble(cmd[3])));
 					break;
 				case "list":
-					Collections.sort(storage,new NameComparator());
+					if (cmd.length>1)
+					{
+						Comparator<Beer> cmp=null;
+						switch(cmd[1])
+						{
+							case "name":
+								cmp=new NameComparator();
+								break;
+							case "style":
+								cmp=new StyleComparator();
+								break;
+							case "strength":
+								cmp=new StrengthComparator();
+								break;
+							default:
+								break;
+						}
+						Collections.sort(storage, cmp);
+					}
 					for(Beer element: storage)
 						System.out.println(element);
 					break;
diff --git a/4. labor/BeerRegister/src/beerregister/NameComparator.java b/4. labor/BeerRegister/src/beerregister/NameComparator.java
index cf372ceab60c0b458c5601e80e5095a9f62d2f97..cc4e97eeadf4a776313d3150b08957ffd6afcea0 100644
--- a/4. labor/BeerRegister/src/beerregister/NameComparator.java	
+++ b/4. labor/BeerRegister/src/beerregister/NameComparator.java	
@@ -3,10 +3,8 @@ package beerregister;
 import java.util.Comparator;
 
 public class NameComparator implements Comparator<Beer>{
-
 	@Override
 	public int compare(Beer t, Beer t1) {
 		return t.name.compareTo(t1.name);
 	}
-	
 }
diff --git a/4. labor/BeerRegister/src/beerregister/StrengthComparator.java b/4. labor/BeerRegister/src/beerregister/StrengthComparator.java
index f51a7b44c06a744d7c6d4833874b6735923a6823..ff1ddab4d56f2177a7d864f0e1a77a1bbc5c67e9 100644
--- a/4. labor/BeerRegister/src/beerregister/StrengthComparator.java	
+++ b/4. labor/BeerRegister/src/beerregister/StrengthComparator.java	
@@ -4,7 +4,6 @@ package beerregister;
 import java.util.Comparator;
 
 public class StrengthComparator implements Comparator<Beer>{
-
 	@Override
 	public int compare(Beer t, Beer t1) {
 		if(t.strength==t1.strength)
@@ -14,5 +13,4 @@ public class StrengthComparator implements Comparator<Beer>{
 		else 
 			return 1;
 	}
-	
 }
diff --git a/4. labor/BeerRegister/src/beerregister/StyleComparator.java b/4. labor/BeerRegister/src/beerregister/StyleComparator.java
index d4d3fd626fe67d0117f92cb48843744b6fe1400f..2861fa2e229bda8fbd329a0857d44339ac538590 100644
--- a/4. labor/BeerRegister/src/beerregister/StyleComparator.java	
+++ b/4. labor/BeerRegister/src/beerregister/StyleComparator.java	
@@ -3,11 +3,8 @@ package beerregister;
 import java.util.Comparator;
 
 public class StyleComparator implements Comparator<Beer>{
-
 	@Override
 	public int compare(Beer t, Beer t1) {
 		return t.style.compareTo(t1.style);
 	}
-	
-	
 }