@misc{indiciae279890ac1928,
  title = {Preliminary structure contour map of the Dunkirk-Chester region, Toole and Liberty Counties, Montana},
  author = {Charles Edgar Erdmann},
  year = {1939},
  doi = {10.3133/ofr391},
  url = {https://pubs.usgs.gov/publication/ofr391},
  note = {Source identifier: ofr391}
}