@misc{indiciae385f477130bc,
  title = {Geologic map of the Triangle A pegmatite, Custer County, South Dakota},
  author = {A.J. Lang},
  year = {1955},
  doi = {10.3133/mf44},
  url = {https://pubs.usgs.gov/publication/mf44},
  note = {Source identifier: mf44}
}