سعيد علي نجاة. 2009. “Measuring the Intensity of Attention After the Aerobic and Non-Aerobic Effort, the Relationship Between Them, and the Intensity Recurrence Period of Football Players”. College of Basic Education Research Journal 8 (1):238-60. https://stats.uomosul.edu.iq/index.php/berj/article/view/39212.