1. Anderson, B. B. (1964). J. clin. Path., 17, 14.
2. BoczarosN, B. (1961). Ibid., 14, 189.
3. Davis, R. E., and Nicol, D. J. (1966). Lancet, 2, 230.
4. Forshaw, J., and Harwood, L. (1966). Ibid., 1, 602.
5. Herbert, V., Gottlieb, C. W., and Altschule, M. B. (1965). Ibid., 2, 1052.