@misc{indiciaebc019dd8523a,
  title = {Mining and related problems of the shallow hydrogeologic regime, Allegheny County, Pennsylvania},
  author = {Seymour Subitzky},
  year = {1975},
  doi = {10.3133/mf641c},
  url = {https://pubs.usgs.gov/publication/mf641C},
  note = {Source identifier: mf641C}
}