REFERENCES
- Bryceson, A. (1987). In Advanced medicine 23, ed. R. E. Pounder & P. L. Chiodini, pp. 336–343. London: Baillière Tindall.
- Freedman, B. J. (1984). British Medical Journal, 288, 696–698.
- Heymann, D. L., Khoromana, G. O., Wirima, J. J. & Campbell, C. C. (1987). Transactions of the Royal Society of Tropical Medicine and Hygiene, 81, 722–724.
- Khoromana, C. O., Campbell, C. C., Wirima, J. J. & Heymann, D. L. (1986). American Journal of Tropical Medicine and Hygiene, 35, 465–471.
- Phillips-Howard, P. A., Bradley, D. J., Blaze, M. & Hurn, M. (1988). British Medical Journal, 296, 245–248.
- World Health Organization (1987). Vaccination certificate requirements and health advice for international travel. Geneva: World Health Organization.