@misc{indiciaeaf97bd9f42b0,
  title = {Isotopic evidence for the source of sulfur in the Upper Freeport coal bed (west-central Pennsylvania, U.S.A.)},
  author = {E.C. Spiker and B.S. Pierce and A. L. Bates and R.W. Stanton},
  year = {1994},
  doi = {10.1016/0009-2541(94)90045-0},
  url = {https://pubs.usgs.gov/publication/70017123},
  note = {Source identifier: 70017123}
}