@misc{indiciaef433b925b3cc,
  title = {Preliminary geologic map of the Bergen Park area, Jefferson and Clear Creek Counties, Colorado},
  author = {Douglas M. Sheridan and John Calvin Reed},
  year = {1971},
  doi = {10.3133/ofr71256},
  url = {https://pubs.usgs.gov/publication/ofr71256},
  note = {Source identifier: ofr71256}
}