الإتاحة: https://doi.org/10.2202/1546-5616.1118Test
الإتاحة: http://www.sciencedirect.com/science/article/pii/S0306-2619Test(08)00104-9
الإتاحة: http://www.sciencedirect.com/science/article/pii/S0167811614000482Test
الإتاحة: http://www.sciencedirect.com/science/article/pii/S0167811614000305Test