APA (7th ed.) Citation

Keegan, J. (1983). Six armies in normandy: From D-Day to the Liberation of Paris. Penguin Books.

Chicago Style (17th ed.) Citation

Keegan, John. Six Armies in Normandy: From D-Day to the Liberation of Paris. England: Penguin Books, 1983.

MLA (9th ed.) Citation

Keegan, John. Six Armies in Normandy: From D-Day to the Liberation of Paris. Penguin Books, 1983.

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