Vicente German-soto Autonomous University of Coahuila   Unidad Camporredondo, Edificio “E”, Saltillo, Coahuila 25000 México   vicentegerman@uadec.edu.mx   http://works.bepress.com/vicente_german_soto           JEL Areas: A2 : Economics Education and Teaching of Economics: General R1 : General Regional Economics (includes Regional Data)