APA (7th ed.) Citation

the Elder, P., & Healy, J. F. (1991). Natural history: Selection. Penguin Books.

Chicago Style (17th ed.) Citation

the Elder, Pliny, and John F. Healy. Natural History: Selection. London: Penguin Books, 1991.

MLA (9th ed.) Citation

the Elder, Pliny, and John F. Healy. Natural History: Selection. Penguin Books, 1991.