Ahmed Qasim Kadhim. “The Effect of Varied Fartlek Method Exercises on VO2max and Specific Endurance in Young Football Players”. Pubmedia Jurnal Pendidikan Olahraga 2, no. 4 (July 25, 2025): 17. Accessed June 4, 2026. https://edu.pubmedia.id/index.php/jpo/article/view/1949.