Institution: | 1.Department of Computing and Mathematics, Faculty of Philosophy, Sciences and Letters of Ribeir?o Preto, Univ. of S?o Paulo, 14040-901, Ribeir?o Preto, SP, Brazil ;2.Institute of Mathematics and Statistics, Federal University of Goiás, Avenida Esperan?a s/n, Campus Samambaia, 74690-900, Goiania, Goiás, Brazil ;3.School of Technology, University of Campinas, R. Paschoal Marmo, 1888, 13484-332, Limeira, SP, Brazil ; |