@misc{indiciae18cfceb53dc0,
  title = {Large springs in the Valley and Ridge physiographic province of Pennsylvania},
  author = {D. A. Saad and D. J. Hippe},
  year = {1990},
  doi = {10.3133/ofr90164},
  url = {https://pubs.usgs.gov/publication/ofr90164},
  note = {Source identifier: ofr90164}
}