@misc{indiciae8f8bb30f7304,
  title = {Structure contour map of the base of Mississippian rocks in the Williston basin and adjoining areas of Montana, North Dakota, South Dakota, and Wyoming},
  author = {Robert Paul Kunkel},
  year = {1954},
  doi = {10.3133/om165},
  url = {https://pubs.usgs.gov/publication/om165},
  note = {Source identifier: om165}
}