1. Department of Mathematics, College of Science, Northern Border University, P.O. Box 1321, Arar 73222, Saudi Arabia
2. Department of Mathematics, Faculty of Science, University of Gabès, Gabès 6072, Tunisia
3. Laboratory of Partial Differential Equations (Lr03es04), Faculty of Science of Tunis, University of Tunis El Manar, Tunis 1068, Tunisia