1. Department of Mathematics, COMSATS University Islamabad, Islamabad 44000, Pakistan
2. Department of Mathematics, Abdul Wali Khan University, Mardan 23200, Pakistan
3. Department of Electrical Engineering, College of Engineering, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
4. Department of Applied Mathematics, University Politehnica of Bucharest, 060042 Bucharest, Romania