Geological Survey (U.S.) & Nicholson, S. W. (2004). Bedrock geologic map of the Port Wing, Solon Springs, and parts of the Duluth and Sandstone 30ʹ X 60ʹ quadrangles, Wisconsin. U.S. Geological Survey.
Chicago Style (17th ed.) CitationGeological Survey (U.S.) and Suzanne W. Nicholson. Bedrock Geologic Map of the Port Wing, Solon Springs, and Parts of the Duluth and Sandstone 30ʹ X 60ʹ Quadrangles, Wisconsin. Reston, Va.: U.S. Geological Survey, 2004.
MLA (9th ed.) CitationGeological Survey (U.S.) and Suzanne W. Nicholson. Bedrock Geologic Map of the Port Wing, Solon Springs, and Parts of the Duluth and Sandstone 30ʹ X 60ʹ Quadrangles, Wisconsin. U.S. Geological Survey, 2004.
Warning: These citations may not always be 100% accurate.