APA (7th ed.) Citation

Kagan, D. (1962). Decline and fall of the Roman Empire: Why did it collapse? Heath.

Chicago Style (17th ed.) Citation

Kagan, Donald. Decline and Fall of the Roman Empire: Why Did It Collapse? Boston: Heath, 1962.

MLA (9th ed.) Citation

Kagan, Donald. Decline and Fall of the Roman Empire: Why Did It Collapse? Heath, 1962.

Warning: These citations may not always be 100% accurate.