APA (7th ed.) Citation

Fenner, F., Wittek, R., & Dumbell, K. R. (1989). The orthopoxviruses. Academic Press.

Chicago Style (17th ed.) Citation

Fenner, Frank, Riccardo Wittek, and Keith R. Dumbell. The Orthopoxviruses. San Diego: Academic Press, 1989.

MLA (9th ed.) Citation

Fenner, Frank, et al. The Orthopoxviruses. Academic Press, 1989.