Tammam, A. H., y E. M. Hashem. «The Individual and Combined Effects of PNF Stretching and Plyometric Training on Muscular Power and Flexibility for Volleyball Players». Amazonia Investiga, vol. 9, n.º 36, enero de 2021, pp. 73-82, doi:10.34069/AI/2020.36.12.6.