1. Haddow, A., and Timmis, G. M., Lancet, i, 207 (1953).
2. Galton, D. A. G., and Till, M., Adv. Cancer Res., 4, 83 (1956).
3. Murphy, M. L., Pediatrics, 23, 231 (1959).
4. Alexandrov, V. A., Dokl. Akad. Nauk S.S.S.R., 159, 918 (1964).
5. Alexandrov, V. A., Arkh. Anat. (in the press).