URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8edcfe5803d02f57ac61f17102c7ef08https://doi.org/10.1007/s11914-020-00628-w
URL الوصول: https://explore.openaire.eu/search/publication?articleId=od______1900::f5c87f2ad38055f4d7b57aa2b653bba3https://serval.unil.ch/resource/serval:BIB_6EE593FDA32D.P001/REF.pdf