@misc{indiciae08a0ca657c5b,
  title = {Geologic map of the Hamburg quadrangle, Schuylkill and Berks Counties, Pennsylvania},
  author = {Gary George Lash},
  year = {1987},
  doi = {10.3133/gq1637},
  url = {https://pubs.usgs.gov/publication/gq1637},
  note = {Source identifier: gq1637}
}