@misc{indiciaedaa26fdd606e,
  title = {Preliminary report on the Pierre Shale in North Park, Colorado, and its correlation to Boulder, Middle Park, and Northwest Colorado},
  author = {Dawn H. Madden},
  year = {1979},
  doi = {10.3133/ofr79729},
  url = {https://pubs.usgs.gov/publication/ofr79729},
  note = {Source identifier: ofr79729}
}