1. Alford, R. H., 1970, J. Immunol.
104:698–703.
2. Allwood, G., Asherson, G. L., Davey, J. J., and Goodford, P. J., 1971, Immunology
21:509–516.
3. Amer, M. S., and Byrne, J. E., 1975, Nature (London)
256:421–424.
4. Andersson, B., and Blomgren, H., 1971, Cell. Immunol.
2:411–424.
5. Andersson, J., Möller, G., and Sjöberg, O., 1972, Transplant. Rev.
11:131–177.