@misc{indiciaea8dd8cf5c73d,
  title = {Ground-water resources of Cambrian and Ordovician carbonate rocks in the valley and ridge physiographic province of Pennsylvania},
  author = {A.E. Becher},
  year = {1996},
  doi = {10.3133/ofr90109},
  url = {https://pubs.usgs.gov/publication/ofr90109},
  note = {Source identifier: ofr90109}
}