1. Department of Mathematics, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia
2. Department of Mathematics, COMSATS University, Attock Campus, Islamabad, Pakistan
3. Department of Mathematics, COMSATS University, Lahore Campus, Islamabad, Pakistan
4. Department of Natural Sciences and Humanities, University of Engineering and Technology, Lahore (RCET), Pakistan
5. Department of Mathematics, COMSATS University, Islamabad Vehari Campus, Vehari 61110, Pakistan