1. Basombrio, M. A., Cancer Res., 30, 2458–2462 (1970).
2. Demant, P., Transplant. Rev., 15, 162–200 (1973).
3. Graff, R. J., and Bailey, D. W., Transplant. Rev., 15, 26–49 (1973).
4. Yefenof, E., and Klein, G., Expl Cell. Res., 88, 217–224 (1974).
5. Haywood, G. R., and McKhann, C. F., J. exp. Med., 133, 1171–1187 (1971).