APA (7th ed.) Citation

Childe, V. G., & Clark, G. (1942). What happened in history. Penguin books.

Chicago Style (17th ed.) Citation

Childe, V. Gordon, and Grahame Clark. What Happened in History. Baltimore: Penguin books, 1942.

MLA (8th ed.) Citation

Childe, V. Gordon, and Grahame Clark. What Happened in History. Penguin books, 1942.