@misc{indiciae1c409c110bcf,
  title = {Map of Colorado showing test wells for oil and gas, pipelines, oil and gas fields, and areas of pre-cambrian rocks},
  author = {Flora K. Walker and N. Wood Bass},
  year = {1951},
  doi = {10.3133/om116},
  url = {https://pubs.usgs.gov/publication/om116},
  note = {Source identifier: om116}
}