APA (7th ed.) Citation

Black, D. F. B. (1977). Geologic map of the Heidelberg quadrangle, east-central Kentucky. U.S. Geological Survey.

Chicago Style (17th ed.) Citation

Black, Douglas F. B. Geologic Map of the Heidelberg Quadrangle, East-central Kentucky. Reston, Va.: U.S. Geological Survey, 1977.

MLA (9th ed.) Citation

Black, Douglas F. B. Geologic Map of the Heidelberg Quadrangle, East-central Kentucky. U.S. Geological Survey, 1977.