1. Agricultural Research Council, 1984. The Nutrient Requirements of Ruminant Livestock, Suppl. 1. Commonwealth Agricultural Bureaux, Slough, England.
2. Asplund, J.M., 1994. Principles of Protein Nutrition of Ruminants. CRC Press, 2000 Corporate Blvd., N.W., Boca Raton, FL 33431.
3. Association of Official Analytical Chemists, 1980. Official Methods of Analysis, 13th edn. AOAC, Washington, DC, pp. 125–142.
4. Estimation of composition, digestibility and feeding value of forages by near infrared reflectance spectroscopy: I. Estimation of chemical composition and digestibility;Atanassova;Bulg. J. Agric. Sci.,1995
5. Brady, 1976.