Cu Thi Thien Thu, Nguyen Xuan Trach and T.R. Preston 2010  Effects of early weaning on postpartum resumption of reproduction in mother buffaloes and growth of their calves. International Conference on Livestock, Climate Change and Resource Depletion (Editor: Reg Preston),  Champasack University, Pakse, LAO PDR, 9-11 November 2010.  httm://www.mekarn.org/workshops/pakse/html/thu.hua.htm