@misc{indiciae97f3b4463eae,
  title = {Geologic and biostratigraphic map of the Pierre shale in the Canon City-Florence Basin and the Twelvemile Park area, south-central Colorado},
  author = {G. R. Scott and W. A. Cobban},
  year = {1975},
  doi = {10.3133/i937},
  url = {https://pubs.usgs.gov/publication/i937},
  note = {Source identifier: i937}
}