APA (7th ed.) Citation

Atkinson, W. C. (1960). A history of Spain & Portugal. Penguin Books.

Chicago Style (17th ed.) Citation

Atkinson, William C. A History of Spain & Portugal. [Middlesex, England]: Penguin Books, 1960.

MLA (9th ed.) Citation

Atkinson, William C. A History of Spain & Portugal. Penguin Books, 1960.