Chhay Ty, Ung Ratha, Vor Sina,  Khieu Borin and Preston T R 2012 Replacing earthworm by water spinach or duckweed on growing frogs with basal diet of rice bran and broken rice.  Proceedings of the International Conference "Livestock-Based Farming Systems, Renewable  Resources and the Environment", 6-9 June 2012, Dalat, Vietnam (Editors: Reg Preston and Sisomphone Southavong) http:/www.mekarn.org/workshops/dalat2012/html/ung.htm