APA (7th ed.) Citation

Geological Survey (U.S.). (1977). State of Pennsylvania. The Survey.

Chicago Style (17th ed.) Citation

Geological Survey (U.S.). State of Pennsylvania. Reston, Va.: The Survey, 1977.

MLA (9th ed.) Citation

Geological Survey (U.S.). State of Pennsylvania. The Survey, 1977.

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