1. Division of Computational Mathematics and Engineering, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam
2. Faculty of Mathematics and Statistics, Ton Duc Thang University, Ho Chi Minh City, Vietnam
3. Faculty of Computer Engineering and Science, Thuy loi University, Hanoi, Vietnam
4. Department of Mathematics, Hanoi National University of Education, Ha Noi, Viet Nam