1. School of Mathematical Sciences, Guizhou Normal University, Guiyang 550001, P. R. China
2. Faculty of Mathematics and Computer Science, University of Science, Ho Chi Minh City, Vietnam
3. Vietnam National University, Ho Chi Minh City, Vietnam
4. Division of Applied Mathematics, Science and Technology Advanced Institute, Van Lang University, Ho Chi Minh City, Vietnam
5. Faculty of Applied Technology, School of Technology, Van Lang University, Ho Chi Minh City, Vietnam
6. Applied Analysis Research Group, Faculty of Mathematics and Statistics, Ton Duc Thang University, Ho Chi Minh City, Vietnam