@misc{indiciaea4cb3fe652a1,
  title = {Aeromagnetic map of parts of the Harrisburg and Baltimore 1 °by 2° quadrangles, Pennsylvania},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1974},
  doi = {10.3133/ofr7413},
  url = {https://pubs.usgs.gov/publication/ofr7413},
  note = {Source identifier: ofr7413}
}