الإتاحة: https://opus.bibliothek.uni-augsburg.de/opus4/frontdoor/index/index/docId/2365Testhttps://nbn-resolving.org/urn:nbn:de:bvb:384-opus4-23654Testhttps://opus.bibliothek.uni-augsburg.de/opus4/files/2365/mpreprint_13_013.pdfTest
الإتاحة: https://opus.bibliothek.uni-augsburg.de/opus4/frontdoor/index/index/docId/1961Testhttps://nbn-resolving.org/urn:nbn:de:bvb:384-opus4-19617Testhttps://opus.bibliothek.uni-augsburg.de/opus4/files/1961/mpreprint_12_007.pdfTest