@misc{indiciaedf13388936ea,
  title = {Direct radiometric measurement by gamma-ray scintillation Spectrometer: Part II: Uranium, Thorium, and Potassium in Common Rocks},
  author = {Patrick M. Hurley},
  year = {1956},
  doi = {10.1130/0016-7606(1956)67[405:drmbgs]2.0.co;2},
  url = {https://pubs.usgs.gov/publication/70216324},
  note = {Source identifier: 70216324}
}