@misc{indiciaeb500f9773621,
  title = {Aeromagnetic and geologic map of east-central Minnesota},
  author = {G. D. Bath and G. M. Schwartz and F. P. Gilbert},
  year = {1964},
  doi = {10.3133/gp474},
  url = {https://pubs.usgs.gov/publication/gp474},
  note = {Source identifier: gp474}
}