الوصول الحر: https://doaj.org/article/bbfa0607bf414d37b1a2be342538d462Test
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e9e766316823505683e1a14cfbfb10e3Testhttps://doi.org/10.1155/2013/847942Test