@misc{indiciaea70c0d770de0,
  title = {Aeromagnetic map of the Quakertown quadrangle, Bucks County, Pennsylvania},
  author = {Randolph Wilson Bromery and G. L. Zandle},
  year = {1959},
  doi = {10.3133/gp214},
  url = {https://pubs.usgs.gov/publication/gp214},
  note = {Source identifier: gp214}
}