@misc{indiciae73eea7c39339,
  title = {Geologic and structure map of the Powder River basin, Southeastern Montana and northeastern Wyoming},
  author = {N.M. Denson and M.L. Gibson and G.L. Sims},
  year = {1992},
  doi = {10.3133/i2281a},
  url = {https://pubs.usgs.gov/publication/i2281A},
  note = {Source identifier: i2281A}
}