APA (7th ed.) Citation

Ridpath, I., & Tirion, W. (2012). The monthly sky guide (9th ed.). Cambridge University Press.

Chicago Style (17th ed.) Citation

Ridpath, Ian, and Wil Tirion. The Monthly Sky Guide. 9th ed. New York: Cambridge University Press, 2012.

MLA (9th ed.) Citation

Ridpath, Ian, and Wil Tirion. The Monthly Sky Guide. 9th ed. Cambridge University Press, 2012.