Nguyen Thi Hong Nhan, Nguyen Trong Ngu, Nguyen Van Hon and Nguyen Thiet 2012 Effects of partial defaunation and different protein supplement sources on rumen cellulolytic bacteria and methanogens investigated by real-time PCR. Proceedings of the International Conference "Livestock-Based Farming Systems, Renewable  Resources and the Environment", 6-9 June 2012, Dalat, Vietnam (Editors: Reg Preston and Sisomphone Southavong) http:/www.mekarn.org/workshops/dalat2012/html/nhanctu1.htm