1. College of Economics, Hue University, 100 Phung Hung street, Hue City, Vietnam, and University of Economics and Law, Vietnam National University, Ho Chi Minh City
2. Hue University of Medicine and Pharmacy, Hue City, Vietnam, and Department of International Health, Tokyo Medical and Dental University, Tokyo, Japan
3. University of Economics and Law, Vietnam National University, Ho Chi Minh City, Vietnam