@misc{indiciae479450f160ad,
  title = {Preliminary geologic map of part of the Rapid City East quadrangle, South Dakota},
  author = {Ernest Dobrovolny},
  year = {1963},
  doi = {10.3133/ofr6328},
  url = {https://pubs.usgs.gov/publication/ofr6328},
  note = {Source identifier: ofr6328}
}