1. Department of Mathematical Sciences, Fatima Jinnah Women University, Rawalpindi 46000, Pakistan e-mail:
2. Research Centre for Modeling and Simulation (RCMS), National University of Sciences and Technology (NUST), Sector H-12, Islamabad 44000, Pakistan
3. Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000, Pakistan; Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80257, Jeddah 21589, Saudi Arabia
4. Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80257, Jeddah 21589, Saudi Arabia