Mustafa, I. M. “Effect of The Percentage of The Contribution of Some Factors in The Implementation of The Lesson of Physical Education: For Middle Schools in Erbil Governorate”. Koya University Journal of Humanities and Social Sciences, vol. 2, no. 2, Dec. 2019, pp. 117-21, doi:10.14500/kujhss.v2n2y2019.pp117-121.