Margarita Villamizar, M.M., Acosta Muñoz, J.F., Cuadros Molano, J.G. and Montoya, J.C. 2009. Motivational factors of professional footballers, as sportsmen and internal customers in Boyaca, Colombia. International Journal of Psychological Research. 2, 2 (Dec. 2009), 148–157. DOI:https://doi.org/10.21500/20112084.870.