@misc{indiciae5c8a74f73d97,
  title = {Radioactivity of coal and associated rock in the coal fields of eastern Kentucky},
  author = {Stewart William Welch},
  year = {1953},
  doi = {10.3133/tei347},
  url = {https://pubs.usgs.gov/publication/tei347},
  note = {Source identifier: tei347}
}