Duong Nguyen Khang 2009 Situation and development trend of biodigesters in Vietnam.   Proceedings MEKARN Workshop on  Livestock, Climate Change and the Environment (Editors: Reg Preston and Vo Lam ), An Giang University, Vietnam, 16-18 November 2009. http://www.mekarn.org/workshops/environ/Abstracts/khan_NLU.htm