الوصول الحر: https://doaj.org/article/8c7bf2682f804f27908eb555dc69f80aTest
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d891afde9523d8b54c78a4757078226dTesthttps://doi.org/10.2298/pan160929019aTest
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ce123826628c90a33503e109f0ff06f3Test