1. State Key Laboratory for Geo-Mechanics and Deep Underground Engineering, and School of Mathematics, China University of Mining and Technology, Xuzhou, China + Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia + Department of Mathematics, College of Science, Kyung Hee University, Seoul, Republic of Korea
2. Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
3. School of Mathematics and Statistics, Qujing Normal University, Qujing, China