APA (7th ed.) Citation

Adams Douglas & Colfer, E. (2009). The hitchhiker's guide to the galaxy. Macmillan.

Chicago Style (17th ed.) Citation

Adams Douglas and Eoin Colfer. The Hitchhiker's Guide to the Galaxy. London: Macmillan, 2009.

MLA (9th ed.) Citation

Adams Douglas and Eoin Colfer. The Hitchhiker's Guide to the Galaxy. Macmillan, 2009.

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