Cita APA (7th ed.)

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

Cita Chicago (17th ed.)

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

Cita MLA (8th ed.)

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