@misc{indiciae21ca73958308,
  title = {Percent-slope map showing historical anthracite coal-mining infrastructure at the northern end of the Lackawanna syncline, Wayne, Susquehanna, and Lackawanna Counties, Pennsylvania},
  author = {Gregory J. Walsh and Mark C. Walsh},
  year = {2023},
  doi = {10.3133/sim3507},
  url = {https://pubs.usgs.gov/publication/sim3507},
  note = {Source identifier: sim3507}
}