URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e5011e6913199bc52efb5ee7aeebbcb3
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f9508212d5acb2291f6f0ccb3864c209http://arxiv.org/abs/0804.3264
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b443d4838cb2a93d2e9f0f284d5a855f