@misc{indiciae19872e5f4cbe,
  title = {Geologic map of the Oil Springs quadrangle, eastern Kentucky},
  author = {William F. Outerbridge},
  year = {1967},
  doi = {10.3133/gq586},
  url = {https://pubs.usgs.gov/publication/gq586},
  note = {Source identifier: gq586}
}