1. Department of Applied Mathematics, University of Science and Technology Beijing, Beijing 100083, China
2. Department of Mathematics, Zhejiang Normal University, Jinhua 321004, Zhejiang, China
3. Department of Mathematics and Statistics, University of South Florida, Tampa, FL 33620, USA
4. School of Mathematics, South China University of Technology, Guangzhou 510640, China
5. College of Mathematics and Systems Science, Shandong University of Science and Technology, Qingdao 266590, Shandong, China
6. International Institute for Symmetry Analysis and Mathematical Modelling, Department of Mathematical Sciences, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho 2735, South Africa
7. Institute of Nonlinear Science, Shaoxing University, Shaoxing 312000, China
8. Department of Mathematics, Beijing University of Chemical Technology, Beijing 100029, China
9. Department of Mathematics and Statistics, Brock University, Saint Catharines, ON, Canada