Bounhong Norachack, Soukanh Keonouchanh, Chhay Ty and  Preston T R 2008 Effect of different levels of water spinach in a basal diet of cassava root meal and rice bran on intake, digestibility and nitrogen balance in growing pigsl.  Proceedings MEKARN Regional Conference 2007: Matching Livestock Systems with Available Resources (Editors: Reg Preston and Brian Ogle), Halong Bay, Vietnam, 25-28 November 2007 http://www.mekarn.org/prohan/boun.htm