Khalil, Waled. “A Comparative Study for Some Kinematical Variables of (400)m Running Between the Iraqi and World Run”. Journal of Physical Education 23, no. 2 (June 28, 2011): 115–128. Accessed June 26, 2026. https://www.jcope.uobaghdad.edu.iq/index.php/jcope/article/view/508.