First Author:   Marcelo de C. Griebeler Federal University of Rio Grande do Sul marcelo.griebeler@ufrgs.br   Av. João Pessoa 52, sala 18D Porto Alegre, 90040000, Brazil   55 51 33083332(Phone) 55 51 33083332(Fax) https://sites.google.com/site/marcelodecgriebeler/home Second Author: Guilherme Stein Foundation of Economic and Statistics guilherme.stein@fee.tche.br   Porto Alegre, 90010281, Brazil       https://sites.google.com/site/steinguilherme/