Sobral, M. F., A. P. C. S. Costa, and A. T. de Almeida Filho. “Multi-Criteria Model for Classifying Clients of Companies Distributing Liquefied Petroleum Gas”. Brazilian Journal of Operations & Production Management, vol. 7, no. 1, Aug. 2010, pp. 53-75, https://bjopm.org.br/bjopm/article/view/V7N1A3.