APA (7th ed.) Citation

Louis, W. R., & Louis, W. R. (1999). The Oxford history of the British Empire. Oxford University Press.

Chicago Style (17th ed.) Citation

Louis, William Roger, and Wm. Roger Louis. The Oxford History of the British Empire. Oxford University Press, 1999.

MLA (9th ed.) Citation

Louis, William Roger, and Wm. Roger Louis. The Oxford History of the British Empire. Oxford University Press, 1999.