1. Department of Mathematics and Physics, University of Information Technology, Ho Chi Minh City, Vietnam
2. Department of Applied Mathematics, Faculty of Applied Science, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City, Vietnam
3. Vietnam National University Ho Chi Minh City, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam
4. Department of Scientific Fundamentals, Posts and Telecommunications Institute of Technology, Hanoi, Vietnam