1. Batey, T., Berryman, C. and Line, C., 1972. The disposal of copperenriched pig-manure slurry on grassland. J. Brit. Grassld Soc. 27, 139–143.
2. Bremner, I., 1979. Copper toxicity studies using domestic and laboratory animals. In: Copper in the Environment Part II. (J.O. Nriagu, ed.) pp. 286–306. (Wiley Intersciences, New York).
3. Bremner, I., Young, B.W. and Mills, C.F., 1976. Protective effect of zinc supplementation against copper toxicosis in sheep. Brit. J. Nutr. 36, 551–561.
4. Dalgarno, A.C. and Mills, C.F., 1975. Retention by sheep of copper by aerobic digests of pig faecal slurry. J. Agric. Sci. 85, 11–18.
5. Feenstra, P. and Ulsen, F.W. Van, 1973. Hay as a cause of copper poisoning in sheep. Tijdschrift voor Diergeneeskunde 98, 632–633.