@misc{indiciae793ae0efbfe9,
  title = {Preliminary stratigraphic section showing radioactive zones in the Devonian black shales in the southern part of the Appalachian basin},
  author = {Roy Clark Kepferle and E.N. Wilson and Frank R. Ettensohn},
  year = {1977},
  doi = {10.3133/ofr77843},
  url = {https://pubs.usgs.gov/publication/ofr77843},
  note = {Source identifier: ofr77843}
}