@misc{indiciaee8c250769317,
  title = {Geologic map of the Pine Grove quadrangle, Schuylkill, Lebanon, and Berks Counties, Pennsylvania},
  author = {Gordon H. Wood and Thomas M. Kehn},
  year = {1968},
  doi = {10.3133/gq691},
  url = {https://pubs.usgs.gov/publication/gq691},
  note = {Source identifier: gq691}
}