Najera, R. J., F. Mondaca, C. Jimenez, M. Conchas, S. I. Aguirre, Y. Rangel, and M. C. Soto. “Motives for Male and Female University Students Engaging in Physical Exercise”. European Scientific Journal, ESJ, Vol. 15, no. 30, Oct. 2019, p. 32, https://eujournal.org/index.php/esj/article/view/12521.