APA (7th ed.) Citation

Gradstein, F. M., Ogg, J. G., & Smith, A. G. (2004). A geologic time scale 2004. Cambridge University Press.

Chicago Style (17th ed.) Citation

Gradstein, F. M., James G. Ogg, and A. Gilbert Smith. A Geologic Time Scale 2004. Cambridge, UK ; New York: Cambridge University Press, 2004.

MLA (9th ed.) Citation

Gradstein, F. M., et al. A Geologic Time Scale 2004. Cambridge University Press, 2004.