الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a7fcedeb37fcbac8ad6ab55701e7b636Testhttp://www.sciencedirect.com/science/article/pii/S0753332218344676Test
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::42a8da71a5f848c95a03adaf209e1525Testhttp://www.sciencedirect.com/science/article/pii/S0753332220302201Test
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::2c0596f9b9b12aab275fe45384d371e0Testhttp://www.sciencedirect.com/science/article/pii/S0753332219322607Test