José Sérgio Oliveira Universidade Federal da Bahia   Av. Reitor Miguel Calmon, s/n Vale do Canela sala 32 Salvador, Bahia 40110903 Brasil   js_cdo@hotmail.com             JEL Areas: E3 : Prices, Business Fluctuations, and Cycles: General (includes Measurement and Data) E1 : General Aggregative Models: General