diff --git a/Account/Account.php b/Account/Account.php
index 2ce5905c6..98a9557c7 100644
--- a/Account/Account.php
+++ b/Account/Account.php
@@ -21,7 +21,10 @@ use phpOMS\Localization\NullLocalization;
 use phpOMS\Validation\Network\Email;
 
 /**
- * Account manager class.
+ * Account class.
+ * 
+ * The account class is the base model for accounts. This model contains the most common account 
+ * information. This model is not comparable to a profile which contains much more information. 
  *
  * @category   Framework
  * @package    phpOMS\Account
@@ -156,6 +159,8 @@ class Account implements ArrayableInterface, \JsonSerializable
 
     /**
      * Constructor.
+     * 
+     * The constructor automatically sets the created date as well as the last activity to now.
      *
      * @param int $id Account id
      *
@@ -183,6 +188,8 @@ class Account implements ArrayableInterface, \JsonSerializable
 
     /**
      * Get localization.
+     * 
+     * Every account can have a different localization which can be accessed here.
      *
      * @return Localization
      *
@@ -195,8 +202,11 @@ class Account implements ArrayableInterface, \JsonSerializable
 
     /**
      * Get groups.
+     * 
+     * Every account can belong to multiple groups. 
+     * These groups usually are used for permissions and categorize accounts.
      *
-     * @return array
+     * @return array Returns array of all groups
      *
      * @since  1.0.0
      */
@@ -221,6 +231,8 @@ class Account implements ArrayableInterface, \JsonSerializable
 
     /**
      * Set permissions.
+     * 
+     * The method accepts an array of permissions. All existing permissions are replaced.
      *
      * @param PermissionAbstract[] $permissions
      *
@@ -235,8 +247,10 @@ class Account implements ArrayableInterface, \JsonSerializable
 
     /**
      * Add permissions.
+     * 
+     * Adds permissions to the account
      *
-     * @param PermissionAbstract[] $permissions
+     * @param PermissionAbstract[] $permissions Array of permissions to add to the account
      *
      * @return void
      *
@@ -249,8 +263,10 @@ class Account implements ArrayableInterface, \JsonSerializable
 
     /**
      * Add permission.
+     * 
+     * Adds a single permission to the account
      *
-     * @param PermissionAbstract $permission
+     * @param PermissionAbstract $permission Permission to add to the account
      *
      * @return void
      *
@@ -264,15 +280,17 @@ class Account implements ArrayableInterface, \JsonSerializable
     /**
      * Has permissions.
      *
-     * @param int $permission Check if user has this permission
-     * @param int $unit Unit
-     * @param string $app App
-     * @param int $module Module
-     * @param int $type Type (e.g. customer)
-     * @param int $element (e.g. customer id)
-     * @param int $component (e.g. address)
+     * Checks if the account has a permission defined
+     * 
+     * @param int $permission Permission to check
+     * @param int $unit Unit Unit to check (null if all are acceptable)
+     * @param string $app App App to check  (null if all are acceptable)
+     * @param int $module Module Module to check  (null if all are acceptable)
+     * @param int $type Type (e.g. customer) (null if all are acceptable)
+     * @param int $element (e.g. customer id) (null if all are acceptable)
+     * @param int $component (e.g. address) (null if all are acceptable)
      *
-     * @return bool
+     * @return bool Returns true if the account has the permission, false otherwise
      *
      * @since  1.0.0
      */
@@ -403,6 +421,8 @@ class Account implements ArrayableInterface, \JsonSerializable
      * @param string $email Email
      *
      * @return void
+     * 
+     * @throws \InvalidArgumentException Exception is thrown if the provided string is not a valid email
      *
      * @since  1.0.0
      */
diff --git a/Account/AccountManager.php b/Account/AccountManager.php
index fdd39b316..7c25d8b9b 100644
--- a/Account/AccountManager.php
+++ b/Account/AccountManager.php
@@ -21,6 +21,8 @@ use phpOMS\DataStorage\Session\SessionInterface;
 
 /**
  * Account manager class.
+ * 
+ * The account manager is used to manage multiple accounts. 
  *
  * @category   Framework
  * @package    phpOMS\Account
@@ -47,14 +49,6 @@ class AccountManager implements \Countable
      */
     private $session = null;
 
-    /**
-     * Database connection instance.
-     *
-     * @var ConnectionAbstract
-     * @since 1.0.0
-     */
-    private $connection = null;
-
     /**
      * Authenticator.
      *
@@ -66,16 +60,14 @@ class AccountManager implements \Countable
     /**
      * Constructor.
      *
-     * @param ConnectionAbstract $connection Database connection
      * @param SessionInterface   $session    Session
      *
      * @since  1.0.0
      */
-    public function __construct(ConnectionAbstract $connection, SessionInterface $session)
+    public function __construct(SessionInterface $session)
     {
-        $this->connection = $connection;
         $this->session    = $session;
-        $this->auth       = new Auth($this->connection, $this->session);
+        $this->auth       = new Auth($this->session);
     }
 
     /**
diff --git a/Account/PermissionAbstract.php b/Account/PermissionAbstract.php
index d05137505..3770feba6 100644
--- a/Account/PermissionAbstract.php
+++ b/Account/PermissionAbstract.php
@@ -16,9 +16,10 @@ declare(strict_types=1);
 namespace phpOMS\Account;
 
 /**
- * InfoManager class.
- *
- * Handling the info files for modules
+ * Permission class.
+ * 
+ * This permission abstract is the basis for all permissions. Contrary to it's name it is not an
+ * abstract class and can be used directly if needed.
  *
  * @category   Framework
  * @package    phpOMS\Module
@@ -26,7 +27,7 @@ namespace phpOMS\Account;
  * @link       http://orange-management.com
  * @since      1.0.0
  */
-abstract class PermissionAbstract
+class PermissionAbstract
 {
     /**
      * Permission id.
diff --git a/Auth/Auth.php b/Auth/Auth.php
index c5b64706d..581d5a452 100644
--- a/Auth/Auth.php
+++ b/Auth/Auth.php
@@ -39,26 +39,16 @@ class Auth
      */
     private $session = null;
 
-    /**
-     * Database connection instance.
-     *
-     * @var ConnectionAbstract
-     * @since 1.0.0
-     */
-    private $connection = null;
-
     /**
      * Constructor.
      *
-     * @param ConnectionAbstract $connection Database connection
      * @param SessionInterface   $session    Session
      *
      * @since  1.0.0
      */
-    public function __construct(ConnectionAbstract $connection, SessionInterface $session)
+    public function __construct(SessionInterface $session)
     {
-        $this->connection = $connection;
-        $this->session    = $session;
+        $this->session = $session;
     }
 
     /**
diff --git a/Business/Marketing/Metrics.php b/Business/Marketing/Metrics.php
index 41f7872ae..7a0124756 100644
--- a/Business/Marketing/Metrics.php
+++ b/Business/Marketing/Metrics.php
@@ -16,7 +16,9 @@ declare(strict_types=1);
 namespace phpOMS\Business\Marketing;
 
 /**
- * Net Promoter Score
+ * Marketing Metrics
+ * 
+ * This class provided basic marketing metric calculations
  *
  * @category   Framework
  * @package    phpOMS\Business
diff --git a/Business/Marketing/NetPromoterScore.php b/Business/Marketing/NetPromoterScore.php
index 7063632af..0c22eee8d 100644
--- a/Business/Marketing/NetPromoterScore.php
+++ b/Business/Marketing/NetPromoterScore.php
@@ -17,6 +17,9 @@ namespace phpOMS\Business\Marketing;
 
 /**
  * Net Promoter Score
+ * 
+ * The net promoter score is a basic evaluation of the happiness of customers. 
+ * Instead of customers the NPS can also be transferred to non-customers.
  *
  * @category   Framework
  * @package    phpOMS\Business
diff --git a/Business/Programming/Metrics.php b/Business/Programming/Metrics.php
index 3801affb2..04b1056ad 100644
--- a/Business/Programming/Metrics.php
+++ b/Business/Programming/Metrics.php
@@ -12,9 +12,13 @@
  * @link       http://orange-management.com
  */
 declare(strict_types=1);
+
 namespace phpOMS\Business\Programming;
+
 /**
  * Programming metrics
+ * 
+ * This class provides basic programming metric calculations.
  *
  * @category   Framework
  * @package    phpOMS\Business
diff --git a/Business/Sales/MarketShareEstimation.php b/Business/Sales/MarketShareEstimation.php
index 268923691..2e8eef0d9 100644
--- a/Business/Sales/MarketShareEstimation.php
+++ b/Business/Sales/MarketShareEstimation.php
@@ -12,9 +12,14 @@
  * @link       http://orange-management.com
  */
 declare(strict_types=1);
+
 namespace phpOMS\Business\Sales;
+
 /**
  * Market share calculations (Zipf function)
+ * 
+ * This class can be used to calculate the market share based on a rank or vice versa 
+ * the rank based on a marketshare in a Zipf distributed market.
  *
  * @category   Framework
  * @package    phpOMS\Business
@@ -24,11 +29,11 @@ namespace phpOMS\Business\Sales;
  */
 class MarketShareEstimation {
     /**
-     * Calculate rank (r) based on marketshare (m)
+     * Calculate rank (r) based on market share (m)
      *
      * @latex  r = \sqrt[s]{\frac{1}{m \times \sum_{n=1}^N{\frac{1}{n^{s}}}}}
      *
-     * @param int $participants (p)
+     * @param int $participants (N)
      * @param float $marketShare (m)
      * @param float $modifier (s)
      *
@@ -47,11 +52,11 @@ class MarketShareEstimation {
     }
     
     /**
-     * Calculate marketshare (m) based on rank (r)
+     * Calculate market share (m) based on rank (r)
      *
      * @latex  m = \frac{\frac{1}{r^{s}}}{\sum_{n=1}^N{\frac{1}{n^{s}}}}
      *
-     * @param int $participants (p)
+     * @param int $participants (N)
      * @param int $rank (r)
      * @param float $modifier (s)
      *
diff --git a/Message/Mail/EmailAbstract.php b/Message/Mail/EmailAbstract.php
index 8fe899e90..7ec52fb59 100644
--- a/Message/Mail/EmailAbstract.php
+++ b/Message/Mail/EmailAbstract.php
@@ -24,7 +24,7 @@ namespace phpOMS\Message\Mail;
  * @link       http://orange-management.com
  * @since      1.0.0
  */
-class MailAbstract
+class EmailAbstract
 {
     /**
      * Host.
diff --git a/System/File/Ftp/Directory.php b/System/File/Ftp/Directory.php
index 62c66da32..1bb4e144b 100644
--- a/System/File/Ftp/Directory.php
+++ b/System/File/Ftp/Directory.php
@@ -96,7 +96,7 @@ class Directory extends FileAbstract implements DirectoryInterface
     /**
      * {@inheritdoc}
      */
-    public static function permission(string $path) : string
+    public static function permission(string $path) : int
     {
         // TODO: Implement permission() method.
     }
diff --git a/System/File/Ftp/File.php b/System/File/Ftp/File.php
index 3ec647e02..94378dbce 100644
--- a/System/File/Ftp/File.php
+++ b/System/File/Ftp/File.php
@@ -192,9 +192,9 @@ class File extends FileAbstract implements FileInterface
     /**
      * {@inheritdoc}
      */
-    public static function permission(string $path) : string
+    public static function permission(string $path) : int
     {
-        return self::parseFtpFileData($path)['permission'] ?? '';
+        return (int) self::parseFtpFileData($path)['permission'] ?? 0;
     }
 
     private static function parseFtpFileData(string $path) : array
diff --git a/Utils/EDI/AnsiX12/EDIAbstract.php b/Utils/EDI/AnsiX12/EDIAbstract.php
index b87c14f6d..df3f8576c 100644
--- a/Utils/EDI/AnsiX12/EDIAbstract.php
+++ b/Utils/EDI/AnsiX12/EDIAbstract.php
@@ -13,7 +13,7 @@
  */
 declare(strict_types=1);
 
-namespace phpOMS\Utils\EDI\AnsiX12\Purchase\PurchaseOrder;
+namespace phpOMS\Utils\EDI\AnsiX12;
 
 /**
  * EDI
diff --git a/Validation/Barcode/Barcode.php b/Validation/Barcode/Barcode.php
index aa9c1bb55..42433e8f7 100644
--- a/Validation/Barcode/Barcode.php
+++ b/Validation/Barcode/Barcode.php
@@ -19,5 +19,8 @@ use phpOMS\Validation\ValidatorAbstract;
 
 class Barcode extends ValidatorAbstract
 {
-
+    public static function isValid($value, array $constraints = null)
+    {
+        
+    }
 }
\ No newline at end of file
diff --git a/Validation/Barcode/Barcode11.php b/Validation/Barcode/Barcode11.php
index adf3bd311..880df57b4 100644
--- a/Validation/Barcode/Barcode11.php
+++ b/Validation/Barcode/Barcode11.php
@@ -19,5 +19,8 @@ use phpOMS\Validation\ValidatorAbstract;
 
 class Barcode11 extends ValidatorAbstract
 {
-
+    public static function isValid($value, array $constraints = null)
+    {
+        
+    }
 }
\ No newline at end of file
diff --git a/Validation/Barcode/Barcode128.php b/Validation/Barcode/Barcode128.php
index cf437f923..291e2e412 100644
--- a/Validation/Barcode/Barcode128.php
+++ b/Validation/Barcode/Barcode128.php
@@ -19,5 +19,8 @@ use phpOMS\Validation\ValidatorAbstract;
 
 class Barcode128 extends ValidatorAbstract
 {
-
+    public static function isValid($value, array $constraints = null)
+    {
+        
+    }
 }
\ No newline at end of file
diff --git a/Validation/Barcode/Barcode25.php b/Validation/Barcode/Barcode25.php
index c9b2293c3..f8d9b9ea0 100644
--- a/Validation/Barcode/Barcode25.php
+++ b/Validation/Barcode/Barcode25.php
@@ -19,5 +19,8 @@ use phpOMS\Validation\ValidatorAbstract;
 
 class Barcode25 extends ValidatorAbstract
 {
-
+    public static function isValid($value, array $constraints = null)
+    {
+        
+    }
 }
\ No newline at end of file
diff --git a/Validation/Barcode/Barcode39.php b/Validation/Barcode/Barcode39.php
index dc1e2a8d6..55699b1ac 100644
--- a/Validation/Barcode/Barcode39.php
+++ b/Validation/Barcode/Barcode39.php
@@ -19,5 +19,8 @@ use phpOMS\Validation\ValidatorAbstract;
 
 class Barcode39 extends ValidatorAbstract
 {
-
+    public static function isValid($value, array $constraints = null)
+    {
+        
+    }
 }
\ No newline at end of file
diff --git a/Validation/Barcode/Barcode93.php b/Validation/Barcode/Barcode93.php
index bcc8325ff..9eda300d3 100644
--- a/Validation/Barcode/Barcode93.php
+++ b/Validation/Barcode/Barcode93.php
@@ -19,5 +19,8 @@ use phpOMS\Validation\ValidatorAbstract;
 
 class Barcode93 extends ValidatorAbstract
 {
-
+    public static function isValid($value, array $constraints = null)
+    {
+        
+    }
 }
\ No newline at end of file
diff --git a/Validation/Barcode/BarcodeCodebar.php b/Validation/Barcode/BarcodeCodebar.php
index ea3b2dc8d..d58afad7d 100644
--- a/Validation/Barcode/BarcodeCodebar.php
+++ b/Validation/Barcode/BarcodeCodebar.php
@@ -19,5 +19,8 @@ use phpOMS\Validation\ValidatorAbstract;
 
 class BarcodeCodebar extends ValidatorAbstract
 {
-
+    public static function isValid($value, array $constraints = null)
+    {
+        
+    }
 }
\ No newline at end of file
diff --git a/Validation/Barcode/BarcodeDatamatrix.php b/Validation/Barcode/BarcodeDatamatrix.php
index e0113f396..e7858613c 100644
--- a/Validation/Barcode/BarcodeDatamatrix.php
+++ b/Validation/Barcode/BarcodeDatamatrix.php
@@ -19,5 +19,8 @@ use phpOMS\Validation\ValidatorAbstract;
 
 class BarcodeDatamatrix extends ValidatorAbstract
 {
-
+    public static function isValid($value, array $constraints = null)
+    {
+        
+    }
 }
\ No newline at end of file
diff --git a/Validation/Barcode/BarcodeEAN.php b/Validation/Barcode/BarcodeEAN.php
index 9605072cf..bcd9a4904 100644
--- a/Validation/Barcode/BarcodeEAN.php
+++ b/Validation/Barcode/BarcodeEAN.php
@@ -19,5 +19,8 @@ use phpOMS\Validation\ValidatorAbstract;
 
 class BarcodeEAN extends ValidatorAbstract
 {
-
+    public static function isValid($value, array $constraints = null)
+    {
+        
+    }
 }
\ No newline at end of file
diff --git a/Validation/Barcode/BarcodeMSI.php b/Validation/Barcode/BarcodeMSI.php
index 04561456f..3c9b35285 100644
--- a/Validation/Barcode/BarcodeMSI.php
+++ b/Validation/Barcode/BarcodeMSI.php
@@ -19,5 +19,8 @@ use phpOMS\Validation\ValidatorAbstract;
 
 class BarcodeMSI extends ValidatorAbstract
 {
-
+    public static function isValid($value, array $constraints = null)
+    {
+        
+    }
 }
\ No newline at end of file
diff --git a/Validation/Barcode/QrCode.php b/Validation/Barcode/QrCode.php
index 2fdda33da..bb67e095a 100644
--- a/Validation/Barcode/QrCode.php
+++ b/Validation/Barcode/QrCode.php
@@ -19,5 +19,8 @@ use phpOMS\Validation\ValidatorAbstract;
 
 class QrCode extends ValidatorAbstract
 {
-
+    public static function isValid($value, array $constraints = null)
+    {
+        
+    }
 }
\ No newline at end of file