1. Faculty of Chemistry, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi, Vietnam
2. College of Education, Vinh University, 182 Le Duan, Vinh, Nghe An, Vietnam
3. The UNE, Armidale, Australia
4. Thanh Do University, QL 32, Kim Chung, Hoai Duc, Ha Noi, Vietnam