@misc{indiciae4dbcd4890320,
  title = {Reconnaissance map of the Dewey Area, Weston and Niobrara counties, Wyoming, and Custer and Fall River counties, South Dakota},
  author = {J.D. Northrop},
  year = {1939},
  doi = {10.3133/ofr3913},
  url = {https://pubs.usgs.gov/publication/ofr3913},
  note = {Source identifier: ofr3913}
}