1. Nowell, P. C., Cancer Res., 20, 462 (1960).
2. Pearmain, G., Lycette, R. R., and Fitzgerald, P. H., Lancet, i, 637 (1963).
3. Bain, B., Vas, M. R., and Lowenstein, L., Blood, 23, 108 (1964).
4. Bach, F., and Hirschhorn, K., Science, 143, 813 (1964).
5. Hirschhorn, K., in Histocompatibility Testing, edit. by Russell, P. S., Winn, H., and Amos, D. B., 177 (National Research Council, Washington, D.C., 1965).