1. School of Mathematical Sciences, Zhejiang Normal University, Jinhua, Zhejiang, P. R. China
2. Department of Mathematics, University of Management and Technology, Sialkot Campus, Lahore, Pakistan
3. National University of Computer and Emerging Sciences, Lahore Campus, Pakistan
4. National University of Computer and Emerging Sciences, Chiniot–Faisalabad Campus, Pakistan
5. Department of Mathematics, King Khalid University, 9004 Abha, Saudi Arabia