@misc{indiciaed001103fae8e,
  title = {Maps showing geologic structure, Bouguer gravity, and aeromagnetic intensity for part of central Kentucky},
  author = {Douglas F. Black and Gordon R. Keller and Robert W. Johnson},
  year = {1976},
  doi = {10.3133/ofr76307},
  url = {https://pubs.usgs.gov/publication/ofr76307},
  note = {Source identifier: ofr76307}
}