M Wanapat, A Petlum and S Chanthai 2005: Effects of levels of urea and coconut oil on rumen ecology, milk yield and composition in lactating dairy cows fed on urea-treated rice straw.  Workshop-seminar "Making better  use of local feed resources" (Editors: Reg Preston and Brian Ogle) MEKARN-CTU, Cantho, 23-25 May, 2005. Article #13. Retrieved, from http://www.mekarn.org/proctu/wana13.htm