Hashm, Ali, et al. “Analytical Study of Some of the Biomechanical Variables of the Start Phase and Their Relation With Achievement of the 50 M Freestyle Swimming In Advance Swimmers”. Journal of Physical Education, vol. 29, no. 4, Dec. 2017, pp. 86-98, https://doi.org/10.37359/JOPE.V29(4)2017.270.