APA (7th ed.) Citation

Butler, A. M. (2007). An unofficial companion to the novels of Terry Pratchett. Greenwood World Pub..

Chicago Style (17th ed.) Citation

Butler, Andrew M. An Unofficial Companion to the Novels of Terry Pratchett. Oxford ; Westport, Conn.: Greenwood World Pub., 2007.

MLA (9th ed.) Citation

Butler, Andrew M. An Unofficial Companion to the Novels of Terry Pratchett. Greenwood World Pub., 2007.