APA (7th ed.) Citation

Roberts, J. M. (1997). The Penguin history of Europe. Penguin Books.

Chicago Style (17th ed.) Citation

Roberts, J. M. The Penguin History of Europe. London, England ; New York, N.Y., USA: Penguin Books, 1997.

MLA (9th ed.) Citation

Roberts, J. M. The Penguin History of Europe. Penguin Books, 1997.