1. Department of Statistics, Applied Math. and Computing, State University of São Paulo (UNESP), Rio Claro, Brazil
2. Department of Statistics, Applied Math. and Computing, State University of São Paulo (UNESP), Rio Claro Brazil
3. DSC, University of Campinas (UNICAMP), Campinas, Brazil
4. DEMAC, State University of São Paulo (UNESP), Rio Claro, Brazil
5. Temple University, Philadelphia, United States