Iv Sophea, Khieu Borin,  Leng​ R A and  Pr​​eston​ T R​​  2010 Effect of different levels of supplementary potassium nitrate replacing urea on growth rates and methane production in goats fed sugar palm-soaked rice straw and mimosa foliage  MSc Thesis, MEKARN-SLU http://www.mekarn.org/MSC2008-10/theses/sophea.htm