APA (7th ed.) Citation

Geological Survey (U.S.), Thomas, R. E., & Englund, K. J. (1999). The lower Pennsylvanian unconformity in the central Appalachian basin. The Survey.

Chicago Style (17th ed.) Citation

Geological Survey (U.S.), Roger E. Thomas, and Kenneth John Englund. The Lower Pennsylvanian Unconformity in the Central Appalachian Basin. Reston, VA: The Survey, 1999.

MLA (9th ed.) Citation

Geological Survey (U.S.), et al. The Lower Pennsylvanian Unconformity in the Central Appalachian Basin. The Survey, 1999.