diff --git a/Models/Arrival.php b/Models/Arrival.php
index 70bf35e..4a982da 100644
--- a/Models/Arrival.php
+++ b/Models/Arrival.php
@@ -52,7 +52,7 @@ class Arrival
     /**
      * Warehouse.
      *
-     * @var   \Modules\Warehousing\Models\Warehouse
+     * @var   Warehouse
      * @since 1.0.0
      */
     private $warehouse = null;
@@ -76,21 +76,13 @@ class Arrival
     /**
      * Warehouse.
      *
-     * @var   \Modules\Warehousing\Models\ArrivalStatus
+     * @var   int
      * @since 1.0.0
      */
-    private ?int $status = null;
+    private int $status = 0;
 
     /* TODO: count, packaging, product count etc.... for every single position + where do you put it */
 
-    /**
-     * Arrival.
-     *
-     * @var   \Modules\Warehousing\Models\Arrival[]
-     * @since 1.0.0
-     */
-    private static array $instances = [];
-
     /**
      * Constructor.
      *
@@ -103,32 +95,6 @@ class Arrival
         $this->id = $id;
     }
 
-    public function init($id) : void
-    {
-    }
-
-    public function __clone()
-    {
-    }
-
-    /**
-     * Initializing object.
-     *
-     * @param int $id Arrival ID
-     *
-     * @return \Modules\Warehousing\Models\Arrival
-     *
-     * @since 1.0.0
-     */
-    public function getInstance($id)
-    {
-        if (!isset(self::$instances[$id])) {
-            self::$instances[$id] = new self($id);
-        }
-
-        return self::$instances[$id];
-    }
-
     /**
      * Get ID.
      *
@@ -222,11 +188,11 @@ class Arrival
     /**
      * Get status.
      *
-     * @return \Modules\Warehousing\Models\ArrivalStatus
+     * @return int
      *
      * @since 1.0.0
      */
-    public function getStatus()
+    public function getStatus() : int
     {
         return $this->status;
     }
@@ -234,13 +200,13 @@ class Arrival
     /**
      * Set status.
      *
-     * @param  \Modules\Warehousing\Models\ArrivalStatus
+     * @param int $status Status
      *
      * @return void
      *
      * @since 1.0.0
      */
-    public function setStatus($status) : void
+    public function setStatus(int $status) : void
     {
         $this->status = $status;
     }
@@ -248,7 +214,7 @@ class Arrival
     /**
      * Get warehouse.
      *
-     * @return \Modules\Warehousing\Models\Warehouse
+     * @return Warehouse
      *
      * @since 1.0.0
      */
@@ -282,24 +248,4 @@ class Arrival
     {
         $this->acceptor = $acceptor;
     }
-
-    public function delete() : void
-    {
-    }
-
-    public function create() : void
-    {
-    }
-
-    public function update() : void
-    {
-    }
-
-    public function serialize() : void
-    {
-    }
-
-    public function unserialize($data) : void
-    {
-    }
 }
diff --git a/Models/Article.php b/Models/Article.php
index 59ad30b..6909260 100644
--- a/Models/Article.php
+++ b/Models/Article.php
@@ -127,14 +127,6 @@ class Article
      */
     private $creator = null;
 
-    /**
-     * Article.
-     *
-     * @var   \Modules\Warehousing\Models\Article[]
-     * @since 1.0.0
-     */
-    private static array $instances = [];
-
     /**
      * Constructor.
      *
@@ -147,32 +139,6 @@ class Article
         $this->id = $id;
     }
 
-    public function init($id) : void
-    {
-    }
-
-    public function __clone()
-    {
-    }
-
-    /**
-     * Initializing object.
-     *
-     * @param int $id Article ID
-     *
-     * @return \Modules\Warehousing\Models\Article
-     *
-     * @since 1.0.0
-     */
-    public function getInstance($id)
-    {
-        if (!isset(self::$instances[$id])) {
-            self::$instances[$id] = new self($id);
-        }
-
-        return self::$instances[$id];
-    }
-
     /**
      * Get ID.
      *
@@ -365,24 +331,4 @@ class Article
             $this->prices[$id] = $price;
         }
     }
-
-    public function delete() : void
-    {
-    }
-
-    public function create() : void
-    {
-    }
-
-    public function update() : void
-    {
-    }
-
-    public function serialize() : void
-    {
-    }
-
-    public function unserialize($data) : void
-    {
-    }
 }
diff --git a/Models/Shipping.php b/Models/Shipping.php
index 80e6f4e..bcc83ef 100644
--- a/Models/Shipping.php
+++ b/Models/Shipping.php
@@ -76,18 +76,10 @@ class Shipping
     /**
      * Warehouse.
      *
-     * @var   \Modules\Warehousing\Models\ArrivalStatus
+     * @var   int
      * @since 1.0.0
      */
-    private ?int $status = null;
-
-    /**
-     * Shipping.
-     *
-     * @var   \Modules\Warehousing\Models\Article[]
-     * @since 1.0.0
-     */
-    private static array $instances = [];
+    private int $status = 0;
 
     /**
      * Constructor.
@@ -101,32 +93,6 @@ class Shipping
         $this->id = $id;
     }
 
-    /**
-     * Initializing object.
-     *
-     * @param int $id Article ID
-     *
-     * @return \Modules\Warehousing\Models\Article
-     *
-     * @since 1.0.0
-     */
-    public static function getInstance($id)
-    {
-        if (!isset(self::$instances[$id])) {
-            self::$instances[$id] = new self($id);
-        }
-
-        return self::$instances[$id];
-    }
-
-    public function init($id) : void
-    {
-    }
-
-    public function __clone()
-    {
-    }
-
     /**
      * Get ID.
      *
@@ -220,11 +186,11 @@ class Shipping
     /**
      * Get status.
      *
-     * @return \Modules\Warehousing\Models\ArrivalStatus
+     * @return int
      *
      * @since 1.0.0
      */
-    public function getStatus()
+    public function getStatus() : int
     {
         return $this->status;
     }
@@ -232,13 +198,13 @@ class Shipping
     /**
      * Set status.
      *
-     * @param  \Modules\Warehousing\Models\ArrivalStatus
+     * @param int $status Status
      *
      * @return void
      *
      * @since 1.0.0
      */
-    public function setStatus($status) : void
+    public function setStatus(int $status) : void
     {
         $this->status = $status;
     }
@@ -246,7 +212,7 @@ class Shipping
     /**
      * Get warehouse.
      *
-     * @return \Modules\Warehousing\Models\Warehouse
+     * @return mixed
      *
      * @since 1.0.0
      */
@@ -280,24 +246,4 @@ class Shipping
     {
         $this->sender = $sender;
     }
-
-    public function delete() : void
-    {
-    }
-
-    public function create() : void
-    {
-    }
-
-    public function update() : void
-    {
-    }
-
-    public function serialize() : void
-    {
-    }
-
-    public function unserialize($data) : void
-    {
-    }
 }
diff --git a/Models/Warehouse.php b/Models/Warehouse.php
index bc998ff..1adf557 100644
--- a/Models/Warehouse.php
+++ b/Models/Warehouse.php
@@ -49,14 +49,6 @@ class Warehouse
      */
     private $location = null;
 
-    /**
-     * Warehouse.
-     *
-     * @var   \Modules\Warehousing\Models\Warehouse[]
-     * @since 1.0.0
-     */
-    private static array $instances = [];
-
     /**
      * Constructor.
      *
@@ -69,32 +61,6 @@ class Warehouse
         $this->id = $id;
     }
 
-    /**
-     * Initializing object.
-     *
-     * @param int $id Warehouse ID
-     *
-     * @return \Modules\Warehousing\Models\Warehouse
-     *
-     * @since 1.0.0
-     */
-    public static function getInstance($id)
-    {
-        if (!isset(self::$instances[$id])) {
-            self::$instances[$id] = new self($id);
-        }
-
-        return self::$instances[$id];
-    }
-
-    public function init($id) : void
-    {
-    }
-
-    public function __clone()
-    {
-    }
-
     /**
      * Get ID.
      *
@@ -184,24 +150,4 @@ class Warehouse
     {
         $this->location = $location;
     }
-
-    public function delete() : void
-    {
-    }
-
-    public function create() : void
-    {
-    }
-
-    public function update() : void
-    {
-    }
-
-    public function serialize() : void
-    {
-    }
-
-    public function unserialize($data) : void
-    {
-    }
 }