@misc{indiciae6aed575422bd,
  title = {Preliminary geologic map of the Barker (7 1/2') quadrangle, Judith Basin and Cascade Counties, Montana},
  author = {Irving J. Witkind},
  year = {1969},
  doi = {10.3133/ofr69320},
  url = {https://pubs.usgs.gov/publication/ofr69320},
  note = {Source identifier: ofr69320}
}