APA (7th ed.) Citation

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

Chicago Style (17th ed.) Citation

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

MLA (9th ed.) Citation

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

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