@misc{indiciae444561294f7e,
  title = {Geologic map of the Delaware quadrangle, western Kentucky},
  author = {William D. Johnson},
  year = {1973},
  doi = {10.3133/gq1087},
  url = {https://pubs.usgs.gov/publication/gq1087},
  note = {Source identifier: gq1087}
}