APA (7th ed.) Citation

Willoughby, A. C. (1950). Orchids and how to grow them. Oxford University Press.

Chicago Style (17th ed.) Citation

Willoughby, Adelaide C. Orchids and How to Grow Them. New York: Oxford University Press, 1950.

MLA (9th ed.) Citation

Willoughby, Adelaide C. Orchids and How to Grow Them. Oxford University Press, 1950.