APA (7th ed.) Citation

Kehn, T. M. (1973). Sturgis Formation (Upper Pennsylvanian): A new map unit in the western Kentucky coal field. U.S. Govt. Print. Off.

Chicago Style (17th ed.) Citation

Kehn, Thomas M. Sturgis Formation (Upper Pennsylvanian): A New Map Unit in the Western Kentucky Coal Field. Washington: U.S. Govt. Print. Off, 1973.

MLA (9th ed.) Citation

Kehn, Thomas M. Sturgis Formation (Upper Pennsylvanian): A New Map Unit in the Western Kentucky Coal Field. U.S. Govt. Print. Off, 1973.