APA (7th ed.) Citation

Geological Survey (U.S.), Caxton Company, & Pezolt, F. (2001). Colorado. The Survey.

Chicago Style (17th ed.) Citation

Geological Survey (U.S.), Caxton Company, and Francis Pezolt. Colorado. Reston, Va.: The Survey, 2001.

MLA (9th ed.) Citation

Geological Survey (U.S.), et al. Colorado. The Survey, 2001.