diff --git a/src/main/java/it/polimi/ingsw/gc14/Model/Cards/Building/Effects/Building0.java b/src/main/java/it/polimi/ingsw/gc14/Model/Cards/Building/Effects/Building0.java
index 292e1a7..9ae8e89 100644
--- a/src/main/java/it/polimi/ingsw/gc14/Model/Cards/Building/Effects/Building0.java
+++ b/src/main/java/it/polimi/ingsw/gc14/Model/Cards/Building/Effects/Building0.java
@@ -2,13 +2,10 @@ package it.polimi.ingsw.gc14.Model.Cards.Building.Effects;
 
 import it.polimi.ingsw.gc14.Model.Cards.Building.EffectType;
 import it.polimi.ingsw.gc14.Model.Cards.BuildingCard;
-import it.polimi.ingsw.gc14.Model.Cards.TribeCards.Characters.Artist;
 import it.polimi.ingsw.gc14.Model.Player;
-import it.polimi.ingsw.gc14.Model.Cards.TribeCards.Character;
 import it.polimi.ingsw.gc14.Model.Cards.TribeCards.CharacterType;
 
-import java.util.ArrayList;
-import java.util.HashMap;
+
 
 /**
  * From the moment you buy this building, every time you complete a set of 6 different characters, you gain 5 food.
@@ -22,7 +19,7 @@ public class Building0 extends BuildingCard {
     boolean purchased ;
 
     /**
-     * The numSet attribute indicates how many complete sets the player already has.
+     * The numSet attribute indicates how many complete sets the player has.
      */
     private int numSet;
 
diff --git a/src/main/java/it/polimi/ingsw/gc14/Model/Cards/Building/Effects/Building4.java b/src/main/java/it/polimi/ingsw/gc14/Model/Cards/Building/Effects/Building4.java
index 33fa499..df86b6f 100644
--- a/src/main/java/it/polimi/ingsw/gc14/Model/Cards/Building/Effects/Building4.java
+++ b/src/main/java/it/polimi/ingsw/gc14/Model/Cards/Building/Effects/Building4.java
@@ -2,15 +2,26 @@ package it.polimi.ingsw.gc14.Model.Cards.Building.Effects;
 
 import it.polimi.ingsw.gc14.Model.Cards.Building.EffectType;
 import it.polimi.ingsw.gc14.Model.Cards.BuildingCard;
-import it.polimi.ingsw.gc14.Model.Cards.TribeCards.Character;
 import it.polimi.ingsw.gc14.Model.Cards.TribeCards.Characters.Inventor;
 import it.polimi.ingsw.gc14.Model.Player;
 
 import java.util.HashMap;
 
+/**
+ * From when you purchase this Building, every time you obtain a pair of identical
+ * Inventors, you gain 3 Food.
+ * This effect doesn't apply on already owned pairs at the time of purchase.
+ */
 public class Building4 extends BuildingCard {
 
+    /**
+     * The purchased attribute is used to indicate whether the card has already been initialized.
+     */
     boolean purchased ;
+
+    /**
+     * The numPair attribute indicates how many Inventors pairs the player has.
+     */
     int numPair;
 
     /**
@@ -25,6 +36,11 @@ public class Building4 extends BuildingCard {
         effectId=4;
     }
 
+    /**
+     * Initializes the building by counting the number of Inventors pairs at the moment of purchase.
+     * The building can only be initialized once.
+     * @param player the player who owns the building, whose cards are counted to determine the number of pairs.
+     */
     public void initialize(Player player)
     {
         if(purchased)
@@ -72,7 +88,12 @@ public class Building4 extends BuildingCard {
         return new Building4(getEra(),getPrice(),getPrestigeValue());
     }
 
-
+    /**
+     * Calculates the current number of pairs and subtracts the previous value (i.e., the number of newly obtained pairs).
+     * The player gains an amount of food equal to 3 times this result.
+     * @param player the player who owns the building
+     * @throws IllegalArgumentException thrown if the specified player does not own this card.
+     */
     @Override
     public void applyEffect(Player player) throws IllegalArgumentException {
         if(!player.buildingCards.contains(this))