1. Marley, W. G., Medical Research Council Report on Hazards to Man of Nuclear and Allied Radiations (Cmd. 9780), 121 (London, 1956).
2. Report of the United Nations Scientific Committee on the Effects of Atomic Radiation, 101 and 109 (1958).
3. Spiers, F. W., Nature, 183, 517 (1959).
4. Vennart, J., Brit. J. Radiol., 30, 55 (1957).
5. Stewart, N. G., Osmond, R. G. D., Crooks, R. N., Fisher, E. M. R., and Owers, M. J., Report A.E.R.E. HP/R 2790, and personally communicated supplementary data. A.E.R.E.—R 3094.