Fatal error: Uncaught Error: Class "APP\plugins\generic\crossref\filter\IssueCrossrefXmlFilter" not found in C:\xampp\htdocs\journal\plugins\generic\crossref\filter\ArticleCrossrefXmlFilter.php:31 Stack trace: #0 {main} thrown in C:\xampp\htdocs\journal\plugins\generic\crossref\filter\ArticleCrossrefXmlFilter.php on line 31