APA (7th ed.) Citation

Thucydides. (1954). History of the Peloponnesian war. Penguin Books.

Chicago Style (17th ed.) Citation

Thucydides. History of the Peloponnesian War. New York: Penguin Books, 1954.

MLA (9th ed.) Citation

Thucydides. History of the Peloponnesian War. Penguin Books, 1954.