APA (7th ed.) Citation

Geological Survey (U.S.), U.S. Coast and Geodetic Survey, & Delaware Geological Survey. (1943). Delaware, 7.5 minute series (topographic). U.S. Geological Survey.

Chicago Style (17th ed.) Citation

Geological Survey (U.S.), U.S. Coast and Geodetic Survey, and Delaware Geological Survey. Delaware, 7.5 Minute Series (topographic). Reston, Va.: U.S. Geological Survey, 1943.

MLA (9th ed.) Citation

Geological Survey (U.S.), et al. Delaware, 7.5 Minute Series (topographic). U.S. Geological Survey, 1943.