@misc{indiciaeab4e3b97e472,
  title = {A preliminary report on a zone containing thick lignite beds, Denver Basin, Colorado},
  author = {Paul E. Soister},
  year = {1974},
  doi = {10.3133/ofr7427},
  url = {https://pubs.usgs.gov/publication/ofr7427},
  note = {Source identifier: ofr7427}
}