1. Department of Mathematics, Faculty of Sciences of Sfax, Sfax University, BP 1171, Sfax, Tunisia
2. Department of Statistics and Operations Research, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
3. ENSIIE, University of Evry-Val-d’Essonne, Évry-Courcouronnes, France