1. DEPARTAMENTO DE MATEMÁTICA, INSTITUTO DE CIÊNCIAS EXATAS; UNIVERSIDADE FEDERAL DE MINAS GERAIS; 31270-901 BELO HORIZONTE MG BRAZIL
2. SCHOOL OF STATISTICS; JIANGXI UNIVERSITY OF FINANCE AND ECONOMICS; NANCHANG JIANGXI 330013 P. R.CHINA
3. RESEARCH CENTER OF APPLIED STATISTICS; JIANGXI UNIVERSITY OF FINANCE AND ECONOMICS; NANCHANG JIANGXI 330013 P. R.CHINA