الوصول الحر: https://www.jstor.org/stable/41061084Test
الوصول الحر: https://gup.ub.gu.se/publication/150800Test
الإتاحة: https://doi.org/10.17615/8171-3735Testhttps://cdr.lib.unc.edu/downloads/xs55mm53k?file=thumbnailTesthttps://cdr.lib.unc.edu/downloads/xs55mm53kTest
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=pmid_dedup__::f09906911bce6a41dfc5918e6341a610Testhttps://pubmed.ncbi.nlm.nih.gov/24014614Test