@misc{indiciae5d3976d8b45d,
  title = {Spectrographic analysis for selected minor elements in Pierre shale},
  author = {Paul R. Barnett},
  year = {1961},
  doi = {10.3133/pp391b},
  url = {https://pubs.usgs.gov/publication/pp391B},
  note = {Source identifier: pp391B}
}