1. Laboratory of Pure and Applied Mathematics, Amar Teledji University, Laghouat 03000, Algeria
2. Department of Mathematics, Sorbonne University, Paris, France
3. Department of Mathematics, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
4. Laboratoire de Mathématiques Appliquées et de Modélisation, Université 8 Mai 1945 Guelma. B.P. 401 Guelma 24000, Algeria