Fatal error: Uncaught Error: Class "ilBiblFileReaderBase" not found in /var/www/html/ilias/components/ILIAS/Bibliographic/classes/FileReader/BibTex/class.ilBiblTexFileReader.php:23 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/Bibliographic/classes/FileReader/BibTex/class.ilBiblTexFileReader.php on line 23