APA (7th ed.) Citation

Christopher, A. J. (1988). The British Empire at its zenith / A.J. Christopher. Croom Helm.

Chicago Style (17th ed.) Citation

Christopher, A. J. The British Empire at Its Zenith / A.J. Christopher. London: Croom Helm, 1988.

MLA (9th ed.) Citation

Christopher, A. J. The British Empire at Its Zenith / A.J. Christopher. Croom Helm, 1988.

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