APA (7th ed.) Citation

Palmer, A. (1990). The Penguin Dictionary of Twentieth-Century History. Penguin Books.

Chicago Style (17th ed.) Citation

Palmer, Alan. The Penguin Dictionary of Twentieth-Century History. London: Penguin Books, 1990.

MLA (9th ed.) Citation

Palmer, Alan. The Penguin Dictionary of Twentieth-Century History. Penguin Books, 1990.