1. Barber, Mary (1947). Brit. med. J., 2, 863.
2. Barber, Mary, and Kuper, S. W. A. (1951). J. Path. Bact., 63, 65.
3. Goslings, W. R. O., and Buchli, K. (1958). Arch. intern. Med., 102,691. Jarvis, Audrey W., and Wigley, R. D. (1961). Lancet, 2, 1168.
4. Johnson, A., Rountree, Phyllis M., Smith, Katherine, Stanley, N. F., and Anderson, K. (1960). Spec. Rep. Ser. No. 10, Nat. Hith med. Res. Coun. (Canberra).
5. Knight, V., White, A. C., and Martin, M. P. (1958). Ann. intern. Med., 49, 536.