@misc{indiciae8a6ca5095ed4,
  title = {Aeromagnetic map of the McNair-Grand Portage area, northeastern Minnesota},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1969},
  doi = {10.3133/gp639},
  url = {https://pubs.usgs.gov/publication/gp639},
  note = {Source identifier: gp639}
}