1. Department for Management of Science and Technology Development, Ton Duc Thang University, Ho Chi Minh City, Vietnam
2. Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Vietnam
3. College of International Cooperation, Jinzhou Medical University, Jinzhou City, Liaoning Province, People’s Republic of China
4. Department of Waste Management and Pollution Control, Gaborone, Botswana