@misc{indiciaed314f11d9f27,
  title = {Aeromagnetic map of Minnesota},
  author = {Isidore Zietz and J.R. Kirby},
  year = {1970},
  doi = {10.3133/gp725},
  url = {https://pubs.usgs.gov/publication/gp725},
  note = {Source identifier: gp725}
}