Geological Survey (U.S.) & ProQuest (Firm). (1907). Economic geology of the Amity quadrangle, eastern Washington County, Pennsylvania. [publisher not identified].
Chicago Style (17th ed.) CitationGeological Survey (U.S.) and ProQuest (Firm). Economic Geology of the Amity Quadrangle, Eastern Washington County, Pennsylvania. Washington: [publisher not identified], 1907.
MLA (9th ed.) CitationGeological Survey (U.S.) and ProQuest (Firm). Economic Geology of the Amity Quadrangle, Eastern Washington County, Pennsylvania. [publisher not identified], 1907.
Warning: These citations may not always be 100% accurate.