@misc{indiciae0617536765bb,
  title = {Map of the Wyodak-Anderson coal bed in the Gillette area, Campbell County, Wyoming},
  author = {N.M. Denson and W. R. Keefer},
  year = {1974},
  doi = {10.3133/i848d},
  url = {https://pubs.usgs.gov/publication/i848D},
  note = {Source identifier: i848D}
}