@misc{indiciaeff797a5f5fa2,
  title = {Geologic map of the Spottsville quadrangle, Henderson County, Kentucky},
  author = {William D. Johnson},
  year = {1973},
  doi = {10.3133/gq1090},
  url = {https://pubs.usgs.gov/publication/gq1090},
  note = {Source identifier: gq1090}
}