M.Y. Al-Khafaji, Wasf, Bushra K. Mohammed, and Naktal J.Y. Al-Khalidi. 2018. “The Effect of Mastery Learning Strategy on the Development of Academic Achievement for Sixth Primary Class Pupils”. College of Basic Education Research Journal 14 (2):307-30. https://doi.org/10.33899/berj.2018.146400.