1. Institute of Numerical Sciences, Department of Mathematics, Gomal University, Dera Ismail Khan 29050, Pakistan
2. Department of Mathematics and Sciences, Prince Sultan University, Riyadh 11586, Saudi Arabia
3. Department of Medical Research, China Medical University, Taichung 40402, Taiwan
4. Department of Mechanical Engineering, Institute of Space Technology, P. O. Box 2750, Islamabad, Pakistan