@misc{indiciae29fe2bd63416,
  title = {Aeromagnetic map of part of the Norristown quadrangle, Philadelphia, Chester, Delaware, and Montgomery Counties, Pennsylvania},
  author = {Randolph Wilson Bromery and G. L. Zandle},
  year = {1959},
  doi = {10.3133/gp201},
  url = {https://pubs.usgs.gov/publication/gp201},
  note = {Source identifier: gp201}
}