APA (7th ed.) Citation

Gribbin, J., & Gribbin, M. (2001). Ice age. Penguin Books.

Chicago Style (17th ed.) Citation

Gribbin, John, and Mary Gribbin. Ice Age. London: Penguin Books, 2001.

MLA (9th ed.) Citation

Gribbin, John, and Mary Gribbin. Ice Age. Penguin Books, 2001.

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