1. Basic Science Department, Modern Academy for Engineering and Technology, Maadi 11585, Egypt
2. Department of Pure Mathematics, University of Calcutta 35, Ballygaunge Circular Road, Kolkata 700019, West Bengal, India
3. Department of Mathematics, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
4. Department of Mathematics, Jadavpur University, Kolkata 700032, West Bengal, India