@misc{indiciae2b6210ea2ec2,
  title = {Preliminary aeromagnetic map covering most of the exposed Precambrian terrane in Wisconsin},
  author = {Isidore Zietz and John H. Karl and Meredith Eggers Ostrom},
  year = {1977},
  doi = {10.3133/mf888},
  url = {https://pubs.usgs.gov/publication/mf888},
  note = {Source identifier: mf888}
}