@misc{indiciaef4c31b3b3416,
  title = {Total intensity aeromagnetic map of Knox County, Indiana and part of Lawrence County, Illinois},
  author = {John R. Henderson and J. L. Meuschke},
  year = {1951},
  doi = {10.3133/gp108},
  url = {https://pubs.usgs.gov/publication/gp108},
  note = {Source identifier: gp108}
}