APA (7th ed.) Citation

Gilbert, M. (1997). A history of the 20th century: Volume 1 1900-1933. HarperCollins.

Chicago Style (17th ed.) Citation

Gilbert, Martin. A History of the 20th Century: Volume 1 1900-1933. London: HarperCollins, 1997.

MLA (8th ed.) Citation

Gilbert, Martin. A History of the 20th Century: Volume 1 1900-1933. HarperCollins, 1997.