First Author:   Sergio Da Silva Graduate Program in Economics, Federal University of Santa Catarina professorsergiodasilva@gmail.com         Second Author: Marcia L. Zindel Department of Production Engineering, University of Brasilia marcialongen@hotmail.com         Third Author: Emilio Menezes Department of Production Engineering, Federal University of Santa Catarina emilio@eps.ufsc.br         Fourth Author: Raul Matsushita Department of Statistics, University of Brasilia raulmta@unb.br