@misc{indiciae2711b2496c96,
  title = {Chemical analysis and geochemical associations in Devonian black shale core samples from Martin County, Kentucky; Carroll and Washington counties, Ohio; Wise County, Virginia; and Overton County, Tennessee},
  author = {Joel S. Leventhal},
  year = {1979},
  doi = {10.3133/ofr791503},
  url = {https://pubs.usgs.gov/publication/ofr791503},
  note = {Source identifier: ofr791503}
}