@misc{indiciae590bf4e4984a,
  title = {An unusual occurrence of arsenic-bearing pyrite in the Upper Freeport coal bed, West-Central Pennsylvania},
  author = {L.F. Ruppert and J.A. Minkin and J. J. McGee and C. B. Cecil},
  year = {2002},
  doi = {10.1021/ef00032a002},
  url = {https://pubs.usgs.gov/publication/70016897},
  note = {Source identifier: 70016897}
}