yusef, Ali, and Maher Abdul Ilah. “The Effect Of Continuous Attention Concentration On Learning Spiking In Volleyball For College of Physical Education & Sport Sciences College University Of Baghdad”. Journal of Physical Education 29, no. 1 (March 28, 2017): 48–65. Accessed June 23, 2026. https://www.jcope.uobaghdad.edu.iq/index.php/jcope/article/view/101.