1. Bennets, H. W. - 1944 -J. Dept. Agr. W. Australia, 21:104.
2. Bennets, H. W. et al. - 1946 -August Vet. J., 22:2.
3. Bradbury, R. B. &White, D. E. - 1954 - Vit. and Horm. advances in Research and application, 1955, 12:207.
4. Dohrn, M. et al., - 1926 - med. clin. (Munich) 22:1417.
5. Cheng, D. et al. - 1953 -J. animal sci., 12:207.