Ismael, Huida, and Mohammed Salman. “Standardizing Psychological Steadfastness Scale for Primer Soccer League Referee”. Journal of Physical Education 30, no. 4 (December 28, 2018): 164–189. Accessed June 21, 2026. https://jcope.uobaghdad.edu.iq/index.php/jcope/article/view/458.