@misc{indiciae97f619920fde,
  title = {Geology of the Precambrian rocks of the Keystone pegmatite district, southern Black Hills, South Dakota},
  author = {James Jennings Norton},
  year = {1957},
  doi = {10.3133/ofr5784},
  url = {https://pubs.usgs.gov/publication/ofr5784},
  note = {Source identifier: ofr5784}
}