@misc{indiciae31fa484c6ca7,
  title = {Structure contour map of the Montana Plains},
  author = {C. E. Dobbin and Charles Edgar Erdmann},
  year = {1955},
  doi = {10.3133/om178b},
  url = {https://pubs.usgs.gov/publication/om178B},
  note = {Source identifier: om178B}
}