@misc{indiciaeee628683ae7d,
  title = {Geologic map of the Langtry quadrangle, Val Verde County, Tex.},
  author = {V. L. Freeman},
  year = {1964},
  doi = {10.3133/i422},
  url = {https://pubs.usgs.gov/publication/i422},
  note = {Source identifier: i422}
}