1. Department of Statistics, Islamia College Peshawar, Peshawar 25000, Pakistan
2. Department of Mathematics, University of Peshawar, Peshawar 25000, Pakistan
3. Department of Mathematics, Huzhou University, Huzhou 313000, China
4. Hunan Provincial Key Laboratory of Mathematical Modeling and Analysis in Engineering, Changsha University of Science and Technology, Changsha 410114, China