1. Department of Statistics, Faculty of Mathematics and Statistics, University of Isfahan, Isfahan, Iran
2. School of Mathematics, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran
3. Department of Statistics, Hakim Sabzevari University, Sabzevar, Iran
4. Jiann-Ping Hsu College of Public Health, Department of Biostatistics, Epidemiology and Environmental Health Sciences, Georgia Southern University, Statesboro, GA, USA