@misc{indiciae089a1e8eb66c,
  title = {Exploratory drilling during 1979 in the McCallum coal field, Jackson County, Colorado},
  author = {Thomas J. Piccirilli},
  year = {1979},
  doi = {10.3133/ofr791629},
  url = {https://pubs.usgs.gov/publication/ofr791629},
  note = {Source identifier: ofr791629}
}