AlJaf, Naween Azad Saleh, and Haider Faeq Al-Shamaa. “The Effect of Varied Training Style on The Development of Aerobic Endurance and Half Marathon Achievement for Men”. Journal of Physical Education, vol. 33, no. 3, Sept. 2021, pp. 149-57, https://doi.org/10.37359/JOPE.V33(3)2021.1198.