1. Department of Mathematics, University of Mianwali, Mianwali 42200, Pakistan
2. Department of Mathematics, COMSATS University Islamabad, Islamabad 44000, Pakistan
3. Department of Mathematics, College of Sciences and Arts Onaizah, Qassim University, P.O. Box 6640, Buraydah 51452, Saudi Arabia
4. Department of Applied Mathematics, University Politehnica of Bucharest, 060042 Bucharest, Romania