1. Institute of Economics, University of Campinas, Campinas, Brazil
2. Department of Economics, Federal University of Sao Paulo, Osasco, Brazil
3. Department of Economics, Federal University of Sao Carlos, Sorocaba, Brazil
4. Department of Economics and Statistics "Cognetti de Martiis", University of Turin, Turin, Italy
5. Polytechnic School, University of Sao Paulo, Sao Paulo, Brazil