APA (7th ed.) Citation

Geological Survey (U.S.). (1977). States of Maryland and Delaware: Base map with highways and contours shaded relief (1973.). The Survey.

Chicago Style (17th ed.) Citation

Geological Survey (U.S.). States of Maryland and Delaware: Base Map with Highways and Contours Shaded Relief. 1973. Reston, Va.: The Survey, 1977.

MLA (9th ed.) Citation

Geological Survey (U.S.). States of Maryland and Delaware: Base Map with Highways and Contours Shaded Relief. 1973. The Survey, 1977.