@misc{indiciae9b0019767678,
  title = {Geology of an area about Yankton, South Dakota},
  author = {H. E. Simpson},
  year = {1954},
  doi = {10.3133/ofr54284},
  url = {https://pubs.usgs.gov/publication/ofr54284},
  note = {Source identifier: ofr54284}
}