الوصول الحر: https://doaj.org/article/20d0b5418988448ba997d10431e212eeTest
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::076cfd1f904ea88a5683a69874303454Testhttp://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-31222012000200002&lng=en&tlng=enTest
الإتاحة: https://doi.org/10.1590/2317-1545v40n1182375Testhttps://doaj.org/article/20d0b5418988448ba997d10431e212eeTest