1. Allcroft, R. & I. C. Buxton: Vet. Rec. 1955, 67, 273.
2. Allcroft, R.: Report from Seminar on Control of Diseases in Cattle and at Pasture 1957, p. 113.
3. Cunningham, I. J.: Advances in Vet. Sci. 1955, 2, 138.
4. Dick, A. T.: Austr. Vet. J. 1952, 28, 30.
5. Dick, A. T.: Ibid. 1953, 29, 18.