@misc{indiciae7c8b0b6e5a02,
  title = {Geology of the Big Spring quadrangle, Kentucky},
  author = {Warren Lee Peterson},
  year = {1964},
  doi = {10.3133/gq261},
  url = {https://pubs.usgs.gov/publication/gq261},
  note = {Source identifier: gq261}
}