1. 16th Ann. Rep. Agric. Res. Inst. N. Ireland, 16 (1942–43).
2. Bolton, W., Hale, R. W., and Common, R. H., Scottish J. Agric., 24, 229 (1944).
3. Woodman, H. E., and Evans, R. E., J. Agric. Sci., 33, 1 (1943).
4. Common, R. H., and Bolton, W., J. Soc. Chem. Ind., 61, 153 (1942).
5. Asplin, F. D., Vet. J., 96, 449 (1940).