@misc{indiciae8dfee0233130,
  title = {Aeromagnetic map of the Allentown quadrangle, Northampton, Lehigh, and Bucks Counties, Pennsylvania},
  author = {Randolph Wilson Bromery and B. L. Bennett},
  year = {1959},
  doi = {10.3133/gp213},
  url = {https://pubs.usgs.gov/publication/gp213},
  note = {Source identifier: gp213}
}