1. Katz, D. & Benacerraf, B. Adv. Immun. 15, 2–94 (1972).
2. Tada, T. in ICN-UCLA Symp. on Molecular and Cellular Biology Vol. VI (eds Sercarz, E. E., Herzenberg, L. A. & Fox, C. F.) 345–361 (Academic, New York, 1977).
3. Landolfo, S., Herberman, R. & Holden, H. J. Immun. 118, 1244–1248 (1977).
4. McNeill, T. A. Nature new Biol. 244, 175–176 (1973).
5. Parker, J. W. & Metcalf, D. Immunology 26, 1039–1049 (1974).