@misc{indiciae8ef10efd49c4,
  title = {Distribution and thickness of Devonian rocks in Williston basin and in central Montana and north-central Wyoming},
  author = {Charles A. Sandberg},
  year = {1961},
  doi = {10.3133/b1112d},
  url = {https://pubs.usgs.gov/publication/b1112D},
  note = {Source identifier: b1112D}
}