@misc{indiciaed30733b6ad9f,
  title = {Preliminary geologic map of the east-central part of the Minnekahta quadrangle, Fall River County, South Dakota},
  author = {V.R. Wilmarth and R.D. Smith},
  year = {1957},
  doi = {10.3133/mf68},
  url = {https://pubs.usgs.gov/publication/mf68},
  note = {Source identifier: mf68}
}