APA (7th ed.) Citation

Griffiths, Roach, & O'Callaghan. (2008). International relations: The key concepts. Routledge.

Chicago Style (17th ed.) Citation

Griffiths, Roach, and O'Callaghan. International Relations: The Key Concepts. London: Routledge, 2008.

MLA (8th ed.) Citation

Griffiths, et al. International Relations: The Key Concepts. Routledge, 2008.