1. Renkonen, K. O., Ann. Med. Exp. Biol. Fenn., 26, 66 (1948).
2. Hungerford, D. A., Donelly, A. J., Nowell, P. C., and Beck, S., Amer. J. Human Genet., 11, 215 (1959).
3. Moorhead, P. S., Nowell, P. C., Mellman, W. J., Battips, and Hungerford, D. A., Exp. Cell. Res., 20, 613 (1960).
4. Nowell, P. C., Cancer Res., 20, 462 (1960).
5. Nakamura, S., Tanaka, K., and Murakawa, S., Nature, 188, 144 (1960).