@misc{indiciae8078da8ef601,
  title = {Geologic setting of the Pierre Shale, northern Great Plains},
  author = {George W. Shurr},
  year = {1980},
  doi = {10.3133/ofr80675},
  url = {https://pubs.usgs.gov/publication/ofr80675},
  note = {Source identifier: ofr80675}
}