@misc{indiciae374c7ae4dbf0,
  title = {Preliminary investigation of the geologic setting and chemical composition of the Pierre Shale, Great Plains region},
  author = {Harry Allison Tourtelot},
  year = {1962},
  doi = {10.3133/pp390},
  url = {https://pubs.usgs.gov/publication/pp390},
  note = {Source identifier: pp390}
}