@misc{indiciaec9c3d3376419,
  title = {Gamma-ray logs from central Bluegrass Region, Kentucky},
  author = {Douglas F. B. Black and Earle Rupert Cressman},
  year = {1964},
  doi = {10.3133/ofr6415},
  url = {https://pubs.usgs.gov/publication/ofr6415},
  note = {Source identifier: ofr6415}
}