Fatal error: Uncaught Error: Class "APP\handler\Handler" not found in C:\xampp\htdocs\journal\plugins\generic\citationStyleLanguage\pages\CitationStyleLanguageHandler.php:36 Stack trace: #0 {main} thrown in C:\xampp\htdocs\journal\plugins\generic\citationStyleLanguage\pages\CitationStyleLanguageHandler.php on line 36