1. Institute of Computing Science and Technology, Guangzhou University, Guangzhou 510006, China
2. Department of Mathematics and Natural Sciences, Prince Mohammad Bin Fahd University, P.O. Box 1664, Al Khobar 31952, Saudi Arabia
3. Department of Basic Sciences, Faculty of Engineering, Hasan Kalyoncu University, Gaziantep TR-27010, Turkey
4. Department of Mathematics, Hannam University, Daejeon 34430, Republic of Korea