APA (7th ed.) Citation

Kehn, T. M. (1977). Geologic map of the Crofton quadrangle, Christian and Hopkins counties, Kentucky. U.S. Geological Survey.

Chicago Style (17th ed.) Citation

Kehn, Thomas M. Geologic Map of the Crofton Quadrangle, Christian and Hopkins Counties, Kentucky. Reston, Va.: U.S. Geological Survey, 1977.

MLA (9th ed.) Citation

Kehn, Thomas M. Geologic Map of the Crofton Quadrangle, Christian and Hopkins Counties, Kentucky. U.S. Geological Survey, 1977.