APA (7th ed.) Citation

Pratchett, T., & Baxter, S. (2012). The long earth. Harper.

Chicago Style (17th ed.) Citation

Pratchett, Terry, and Stephen Baxter. The Long Earth. New York: Harper, 2012.

MLA (9th ed.) Citation

Pratchett, Terry, and Stephen Baxter. The Long Earth. Harper, 2012.