Johnson, W. D., & Kunkel, R. P. (1959). The Square Buttes coal field, Oliver and Mercer Counties, North Dakota. United States Department of the Interior, Geological Survey.
Chicago Style (17th ed.) CitationJohnson, William D., and Robert P. Kunkel. The Square Buttes Coal Field, Oliver and Mercer Counties, North Dakota. Washington, D.C.: United States Department of the Interior, Geological Survey, 1959.
MLA (9th ed.) CitationJohnson, William D., and Robert P. Kunkel. The Square Buttes Coal Field, Oliver and Mercer Counties, North Dakota. United States Department of the Interior, Geological Survey, 1959.
Warning: These citations may not always be 100% accurate.