Nguyen Ky Son, Dinh Van Binh , Nguyen Thi Mui and Ngo Tien Dung 2005: Effect of nitrogen source (biodigester effluent, raw manure, and urea) on biomass yield of Guinea grass. (Panicum maximum), and effect of different heights of cutting on parasite infection in growing goats.  Workshop-seminar "Making better  use of local feed resources" MEKARN-CTU, Cantho, 23-25 May, 2005. Article #17. Retrieved, from http://www.mekarn.org/proctu/son17.htm