Pham Tan Nha and Preston T R 2010 Effect of supplementing rice bran with sweet potato leaf meal and earthworms on growth performance of local Muscovy and Pekin ducks  (Editor: Reg Preston) International Conference on Livestock, Climate Change and Resource Depletion, Champasack University, Pakse, LAO PDR, 9-11 November 2010 . http://www.mekarn.org/workshops/pakse/html/nga.ctu.htm