@misc{indiciae00283929a6ec,
  title = {Geologic map of the Allentown East quadrangle, Lehigh, Northampton, and Bucks Counties, Pennsylvania},
  author = {Avery Drake},
  year = {1999},
  doi = {10.3133/gq1804},
  url = {https://pubs.usgs.gov/publication/gq1804},
  note = {Source identifier: gq1804}
}