José César Cruz junior Federal University of Sao Carlos   Rodovia João Leme dos Santos (SP-264), Km 110 Bairro do Itinga Sorocaba, SP 18052-780 Brazil   cesarcruz@ufscar.br   http://deco.sorocaba.ufscar.br           JEL Areas: Q1 : Agriculture: General C5 : Econometric Modeling: General