@misc{indiciae024431174b56,
  title = {Geochemical analyses and summaries of Mississippian and Pennsylvanian sandstone from Kentucky},
  author = {Jon J. Connor},
  year = {1981},
  doi = {10.3133/ofr811098},
  url = {https://pubs.usgs.gov/publication/ofr811098},
  note = {Source identifier: ofr811098}
}