@misc{indiciae9d7658c18cf7,
  title = {Bedrock geologic map of the Port Wing, Solon Springs, and parts of the Duluth and Sandstone 30' X 60' quadrangles, Wisconsin},
  author = {S. W. Nicholson and W.F. Cannon and L. G. Woodruff and Connie Dicken},
  year = {2004},
  doi = {10.3133/ofr20041303},
  url = {https://pubs.usgs.gov/publication/ofr20041303},
  note = {Source identifier: ofr20041303}
}