APA (7th ed.) Citation

Levi, P., Weaver, W., & Mazower, M. (2000). If not now, when? Penguin.

Chicago Style (17th ed.) Citation

Levi, Primo, William Weaver, and Mark Mazower. If Not Now, When? London: Penguin, 2000.

MLA (8th ed.) Citation

Levi, Primo, et al. If Not Now, When? Penguin, 2000.