@misc{indiciaefe97301ba854,
  title = {Radioactivity of coals and associated rocks in Beaver, Clearfield, and Jefferson Counties, Pennsylvania},
  author = {John C. Ferm},
  year = {1955},
  doi = {10.3133/tei468},
  url = {https://pubs.usgs.gov/publication/tei468},
  note = {Source identifier: tei468}
}