1. CRM, GERAD, and Department of Decision Sciences, HEC Montreal (Quebec), Canada
2. Stochastic Modelling & Statistics group.Lab. PDEASG. Faculty of Sciences, Ibn Tofail University, BP 133, Kénitra, Morocco
3. Département de médecine sociale et préventive, École de Santé Publique de l'Université de Montréal, Montreal(Quebec), Canada
4. Department of Mathematics, Linnæus University, Växjö, Sweden