1. AFRC, 1992. Technical committee on responses to nutrients, Report 9. Nutritive requirements of ruminants animals: Protein. Nutrition Abstracts and Reviews, Series B, 62 787–835.
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. ARC, 1984. The Nutrient Requirements of Ruminant Livestock, Supplement No. 1. Report of the Protein Group of the ARC Working Party. Commonwealth Agricultural Bureaux, Slough, UK, 45 pp.