Al-HashmiS. A., and NaumanS. K. “A Study of Modules over Rings and Their Extensions”. Ukrains’kyi Matematychnyi Zhurnal 70, no. 10 (October 25, 2018): 1299-1312. Accessed November 30, 2020. http://umj.imath.kiev.ua/index.php/umj/article/view/1636.