1. Centre for Nonlinear Systems, Chennai Institute of Technology, Chennai 600 069, Tamilnadu, India
2. Department of Mathematics, Gauhati University, Guwahati, India
3. Department of Mathematics, Faculty of Science and Technology, Phuket Rajabhat University, Phuket-83000, Thailand
4. Eastern Michigan Joint College of Engineering, Beibu Gulf University, Qinzhou 535011, China