Cita APA (7a ed.)

Gribbin, J. R., & Gribbin, M. (2002). Ice age. Penguin Books.

Cita Chicago Style (17a ed.)

Gribbin, John R., y Mary Gribbin. Ice Age. London: Penguin Books, 2002.

Cita MLA (9a ed.)

Gribbin, John R., y Mary Gribbin. Ice Age. Penguin Books, 2002.