@misc{indiciae685aaa808439,
  title = {Principal facts for gravity stations in Adams, Berks, Cumberland, Dauphin Lancaster, Lebanon, and York Counties, south-central Pennsylvania},
  author = {S. L. Snyder and D. L. Daniels},
  year = {1987},
  doi = {10.3133/ofr87511},
  url = {https://pubs.usgs.gov/publication/ofr87511},
  note = {Source identifier: ofr87511}
}