APA (7th ed.) Citation

Geological Survey (U.S.), United States. Army Map Service, United States. National Ocean Service, & Maryland Geological Survey. (1942). Maryland, 7.5 minute series (topographic). U.S. Geological Survey.

Chicago Style (17th ed.) Citation

Geological Survey (U.S.), United States. Army Map Service, United States. National Ocean Service, and Maryland Geological Survey. Maryland, 7.5 Minute Series (topographic). Reston, Va.: U.S. Geological Survey, 1942.

MLA (9th ed.) Citation

Geological Survey (U.S.), et al. Maryland, 7.5 Minute Series (topographic). U.S. Geological Survey, 1942.