1. Department of Mathematics, Anqing Normal University, Anqing, Anhui 246133, China
2. Department of Mathematics, Research Center for Complex Systems and Network Sciences, Southeast University, Nanjing, Jiangsu 210096, China
3. Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
4. Department of Mathematics, Quaid-i-Azam University, Islamabad 44000, Pakistan