@misc{indiciae4ebacb94ed43,
  title = {Regional aeromagnetic map of western Lake Superior and adjacent parts of Minnesota, Michigan, and Wisconsin},
  author = {J.R. Kirby and A. J. Petty},
  year = {1966},
  doi = {10.3133/gp556},
  url = {https://pubs.usgs.gov/publication/gp556},
  note = {Source identifier: gp556}
}