1. Technical committee on responses to nutrients, Report 9. Nutritive requirements of ruminants animals: protein;AFRC;Nutr. Abstr. Rev.,1992
2. Energy and Protein Requirements of Ruminants;AFRC,1993
3. Official Methods of Analysis;AOAC,1997
4. The nutrient requirements of ruminant livestock;ARC,1980
5. The Nutrient Requirements of Ruminant Livestock;ARC,1984