Dinh Tran, Lan ; Minh Huyen, Nguyen Thi ; Chien, Hoang Thi. Barbier, E. B., Acreman, M., & Knowler, D. (1997). Economic valuation of wetlands: A guide for policy makers and planners. Retrieved May 15, 2013 from http://biodiversityeconomics.org/pdf/topics-02-01.pdf (5/4/2004)..
,
2020