Geological Survey & Pennsylvania. Bureau of Topographic and Geologic Survey. (1993). Union County, Pennsylvania. U.S. Geological Survey ; For sale by the Survey.
Chicago Style (17th ed.) CitationGeological Survey and Pennsylvania. Bureau of Topographic and Geologic Survey. Union County, Pennsylvania. Reston, Va. : Denver, Colo.: U.S. Geological Survey ; For sale by the Survey, 1993.
MLA (8th ed.) CitationGeological Survey and Pennsylvania. Bureau of Topographic and Geologic Survey. Union County, Pennsylvania. U.S. Geological Survey ; For sale by the Survey, 1993.
Warning: These citations may not always be 100% accurate.