APA (7th ed.) Citation

Atkinson, W. C. (1965). A history of Spain and Portugal. Penguin Books.

Chicago Style (17th ed.) Citation

Atkinson, William Christopher. A History of Spain and Portugal. [Middlesex, England]: Penguin Books, 1965.

MLA (9th ed.) Citation

Atkinson, William Christopher. A History of Spain and Portugal. Penguin Books, 1965.