@misc{indiciaec85683021b90,
  title = {Organic carbon content of Devonian shale sequence sampled in drill cuttings from eighteen wells in western Pennsylvania},
  author = {George Edwin Claypool and Allan W. Stone},
  year = {1979},
  doi = {10.3133/ofr791665},
  url = {https://pubs.usgs.gov/publication/ofr791665},
  note = {Source identifier: ofr791665}
}