1. Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000, Pakistan
2. Department of Mathematics, COMSATS Institute of Information Technology, Chak Shahzad, Park Road Islamabad 44000, Pakistan
3. Research Centre for Modeling and Simulation (RCMS), National University of Sciences and Technology (NUST), Sector H-12, Islamabad 44000, Pakistan
4. Department of Physics, Faculty of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia