1. School of Mathematics and Statistics, Beijing Institute of Technology, Beijing 100081, P. R. China
2. Department of Mathematics and Statistics, Hazara University Mansehra, KPK, Pakistan
3. Department of Mathematical Sciences, Baluchistan University of Information Technology, Engineering and Management Sciences, 87300 Quetta, Pakistan
4. Department of Mathematics, Jadavpur University, Kolkata 700032, West Bengal, India
5. Ajmal College of Arts and Science, Dhubri 783324, Assam, India