@misc{indiciaef99ea4127d15,
  title = {Nine preliminary aeromagnetic maps covering Aitkin County and parts of Itasca, Kanabec, Koochiching, Mille Lacs, Pine, and St. Louis Counties, Minnesota},
  author = {J. L. Meuschke},
  year = {1950},
  doi = {10.3133/ofr5047},
  url = {https://pubs.usgs.gov/publication/ofr5047},
  note = {Source identifier: ofr5047}
}