1. Bremner, J. M., Total nitrogen. In: Methods of Soil Analysis, Part II. Ed. C. A.Black, No. 9 American Soc. Agronomy, Madison, U.S.A. p. 1164 (1965).
2. Butterworth, M. H., The digestibility of tropical forages. Nutr. Abstr. Rev. 37, 349?68 (1967).
3. Christian, C. S. and Shaw, N. H., Protein status of Australian tropical and subtropical pastures. Proc. Brit. Commonwealth Sci. Official Conf. Australia 1949, 225?40. H.M.S.O. London (1951).
4. Colman, R. L. and Lazenby, A., Factors affecting the response of some tropical and temperate grasses to fertilizer nitrogen. Proc. Intern. Grassland Congr., 11th, Surfers Paradise, 392?7 (1970).
5. Cooper, J. P. and Tainton, N. M., Light and temperature requirements for the growth of tropical and temperate grasses. Herbage Abstr. 38, 167?76 (1968).