1. Warner, A. C. I., J. Gen. Microbiol., 14, 749 (1956).
2. Oxford, A. E., NZ Sci. Rev., 16, 38 (1958).
3. Tillman, A. D., and Mac Vicar, R., J. Anim. Sci., 15, 211 (1956).
4. Hill, M. K., Watson, M. J., and McClymont, G. L., Proc. Austral. Soc. Anim. Prod., 7, 49 (1968).
5. Alexander, F., An Introduction to Veterinary Pharmacology (Livingstone, Edinburgh and London, 1960).