APA (7th ed.) Citation

Butterfield, H., Wight, M., & Bull, H. (1966). Diplomatic investigations: Essays in the theory of international politics. Allen & Unwin.

Chicago Style (17th ed.) Citation

Butterfield, Herbert, Martin Wight, and Hedley Bull. Diplomatic Investigations: Essays in the Theory of International Politics. London: Allen & Unwin, 1966.

MLA (9th ed.) Citation

Butterfield, Herbert, et al. Diplomatic Investigations: Essays in the Theory of International Politics. Allen & Unwin, 1966.