APA (7th ed.) Citation

Pratchett, T., & Kirby, J. (1990). Diggers / Terry Pratchett. Doubleday.

Chicago Style (17th ed.) Citation

Pratchett, Terry, and Josh Kirby. Diggers / Terry Pratchett. London: Doubleday, 1990.

MLA (9th ed.) Citation

Pratchett, Terry, and Josh Kirby. Diggers / Terry Pratchett. Doubleday, 1990.

Warning: These citations may not always be 100% accurate.