@misc{indiciae9615058c0b50,
  title = {Total intensity aeromagnetic map of Putnam County, Indiana},
  author = {John R. Henderson and J. L. Meuschke},
  year = {1950},
  doi = {10.3133/gp41},
  url = {https://pubs.usgs.gov/publication/gp41},
  note = {Source identifier: gp41}
}