1. Kellina, O. I. Med. Parasit. 42, 279–285 (1973).
2. Handman, E., Ceredig, R. & Mitchell, G. F. Aust. J. exp. Biol. med. Sci. 57, 9–29 (1979).
3. Howard, J. G., Hale, C. & Chan-Liew, W. L. Parasite immunology (in the press).
4. Bradley, D. J. Clin. exp. Immun. 30, 130–140 (1977).
5. Bradley, D. J., Taylor, B. A., Blackwell, J., Evans, E. P. & Freeman, J. Clin. exp. Immun. 37, 7–14 (1979).