1. Division of Applied Mathematics, Thu Dau Mot University, Binh Duong Province, Vietnam
2. Department of Mathematics and Computer Science, University of Science, Ho Chi Minh City, Vietnam
3. Vietnam National University, Ho Chi Minh City, Vietnam
4. Department of Mathematics, University of Rajasthan, Jaipur 302004, Rajasthan, India
5. Department of Civil and Environmental Engineering, Seoul National University, South Korea