Uosif, M. ., and A. . Mostafa. “Assessment of Natural Radioactivity Levels in Soil and Chemical Fertilizers Widely Used in Upper Egypt: Natural Radioactivity in Soil and Chemical Fertilizers”. WAS Science Nature (WASSN) ISSN: 2766-7715, vol. 3, no. 1, May 2020, pp. 1-7, http://worldascience.com/journals/index.php/wassn/article/view/10.