1. School of Mathematics, Hangzhou Normal University, Hangzhou 311120, China
2. School of Statistics, Jilin University of Finance and Economics, Changchun 130117, China
3. Department of Mathematical Sciences, College of Applied Sciences, Umm Al-Qura University, Mecca 24382, Saudi Arabia
4. Department of Mathematics, Faculty of Science, University of Assiut, Assiut 71516, Egypt