1. School of Mathematics and Statistics, Nanyang Normal University, Nanyang 4730 61, China
2. Department of Mathematics and Computer Sciences, Faculty of Arts and Sciences, Çankaya University, 06530 Ankara, Turkey
3. Department of Chemical and Materials Engineering, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah 21589, Saudi Arabia
4. Institute of Space Sciences, Magurele, RO-077125 Bucharest, Romania
5. Institute of Software Science, Zhengzhou Normal University, Zhengzhou 450044, China
6. Department of Mathematics and Mechanics, China University of Mining and Technology, Xuzhou 221008, China