1. R. T. Prehn,Biological Problems of Grafting (Les Congrès et Colloques de l'Université de Liège 1959), vol. 12, p. 163.
2. J. R. Batchelor andM. S. Silverman, Ciba Foundation Symposium on Transplantation (Ed.G. E. W. Wolstenholme andM. P. Camerow; London 1962), p. 216.
3. L. J. Old, D. A. Clarke, B. Benacerraf andE. Stockert, Experientia18, 335 (1962).
4. E. Möller, J. natn. Cancer Inst.31, 1053 (1965).
5. J. F. Ferrer andE. Mihich, Cancer Res.28, 1116 (1968).