@misc{indiciae015a3afd9b3b,
  title = {Preliminary stratigraphic cross section showing radioactive zones in the Devonian black shales in eastern Ohio and west-central Pennsylvania},
  author = {John B. Roen and Laure G. Wallace and Wallace De Witt},
  year = {1978},
  doi = {10.3133/oc82},
  url = {https://pubs.usgs.gov/publication/oc82},
  note = {Source identifier: oc82}
}