Sheppard, R. A. (1964). Geology of the Tygarts Valley quadrangle, Kentucky. U.S. Geological Survey.
Chicago Style (17th ed.) CitationSheppard, Richard A. Geology of the Tygarts Valley Quadrangle, Kentucky. Reston, Va.: U.S. Geological Survey, 1964.
MLA (9th ed.) CitationSheppard, Richard A. Geology of the Tygarts Valley Quadrangle, Kentucky. U.S. Geological Survey, 1964.
Warning: These citations may not always be 100% accurate.