diff --git a/Controller.php b/Controller.php
index e182a94..db534cc 100644
--- a/Controller.php
+++ b/Controller.php
@@ -42,7 +42,7 @@ use Modules\Knowledgebase\Models\PermissionState;
  * @link       http://website.orange-management.de
  * @since      1.0.0
  */
-class Controller extends ModuleAbstract implements WebInterface
+final class Controller extends ModuleAbstract implements WebInterface
 {
 
     /**
diff --git a/Models/NullWikiCategory.php b/Models/NullWikiCategory.php
index 4bcbd9e..635ef15 100644
--- a/Models/NullWikiCategory.php
+++ b/Models/NullWikiCategory.php
@@ -22,6 +22,6 @@ namespace Modules\Knowledgebase\Models;
  * @link       http://website.orange-management.de
  * @since      1.0.0
  */
-class NullWikiCategory extends WikiCategory
+final class NullWikiCategory extends WikiCategory
 {
 }
diff --git a/Models/NullWikiDoc.php b/Models/NullWikiDoc.php
index 32b59ba..b0e6539 100644
--- a/Models/NullWikiDoc.php
+++ b/Models/NullWikiDoc.php
@@ -22,6 +22,6 @@ namespace Modules\Knowledgebase\Models;
  * @link       http://website.orange-management.de
  * @since      1.0.0
  */
-class NullWikiDoc extends WikiDoc
+final class NullWikiDoc extends WikiDoc
 {
 }