@misc{indiciaeee71781d1f86,
  title = {Geologic map of the Elk Ridge Quadrangle, Powder River County, Montana},
  author = {M.W. McLellan and W. W. Olive},
  year = {1991},
  doi = {10.3133/i2140},
  url = {https://pubs.usgs.gov/publication/i2140},
  note = {Source identifier: i2140}
}