Khaled, S., and E. Ahmed. “Effectiveness of the of Competitive Style of Learning Teams With Homogeneous and Heterogeneous Groups in the Skillful Achievement of Some Offensive Skills in Basketball”. Al-Rafidain Journal For Sport Sciences, vol. 22, no. 70, Oct. 2019, pp. 55-83, doi:10.33899/rajsport.2019.163286.