Thi-Dieu-Hien Vo, Xuan-Thanh Bui*, Chitsan Lin, Van-Truc Nguyen*, Thi-Khanh-Dieu Hoang, Hai Nguyen, Phuoc Dan Nguyen, Huu Hao Ngo, Wenshan Guo (2019)/A mini-review on shallow-bed constructed wetlands: a promising innovative green roof