@misc{indiciaed79e08206f9a,
  title = {Geologic map of the Swatara Hill quadrangle, Schuylkill and Berks Counties, Pennsylvania},
  author = {Gordon H. Wood and Thomas M. Kehn},
  year = {1968},
  doi = {10.3133/gq689},
  url = {https://pubs.usgs.gov/publication/gq689},
  note = {Source identifier: gq689}
}