1. Snyder, S. P., and Theilen, G. H., Nature, 221, 1074 (1969).
2. Gardner, M. B., Rongey, R. W., Arnstein, P., Estes, J., Sarma, P., Huebner, R. J., and Rickard, C. G., Nature, 226, 807 (1970).
3. Snyder, S. P., Theilen, G. H., and Richards, W. P. C., Cancer Res., 30, 1658 (1970).
4. Theilen, G. H., Snyder, S. P., Wolfe, L. G., and Landon, J. C., Comparative Leukemia Research (edit. by Dutcher, R. M.), (Karger, New York, in the press).
5. Deinhardt, F., Wolfe, L. G., Theilen, G. H., and Snyder, S. P., Science, 167, 881 (1970).