1. Falkow, S.: What is a pathogen? ASM News 63 (1996) 359–365.
2. Hopkins, D. R.: Princes and peasants: smallpox in history. University of Chicago Press, Chicago 1983, pp. 13, 6, 158, 18, 29, 200, 277, 91.
3. Centers for Disease Control and Prevention: Human monkeypox—Kasai Oriental. Democratic Republic of Congo. MMWR 46 (1997) 1168–1171.
4. Douglas, N. J., Richardson, M., Dumbell, K. R.: Evidence for recent genetic variation in monkeypox viruses. J. Gen. Virol. 75 (1996) 1303–1309.
5. Kinman, T. J.: Risks connected with the use of conventional and genetically engineered vaccines. Vet. Q. 14 (1992) 110–118.