Ruiz Vanoye, J. A., Díaz-Parra, O., Fuentes-Penna, A., Vélez-Díaz, D., García Munguía, M., Ruiz-Díaz, J., & Ruiz-Díaz, F. (2018). Motivation Index to Improve the Soccer Performance. International Journal of Combinatorial Optimization Problems and Informatics, 8(3), 45–57. Retrieved from https://ijcopi.org/ojs/article/view/18