Rubiano Ovalle, O., and M. A. Villarreal. “Operative Factors for Service Management Application to a Labor Vocational Training System”. Revista Universidad EAFIT, vol. 45, no. 155, Jan. 2011, pp. 74-93, https://publicaciones.eafit.edu.co/index.php/revista-universidad-eafit/article/view/6.