APA (7th ed.) Citation

Geological Survey (U.S.). (2001). USGS maps. The Survey.

Chicago Style (17th ed.) Citation

Geological Survey (U.S.). USGS Maps. [Reston, Va.]: The Survey, 2001.

MLA (9th ed.) Citation

Geological Survey (U.S.). USGS Maps. The Survey, 2001.

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