@misc{indiciae8e8a12a2509e,
  title = {Oil resources of black shales of the eastern United States},
  author = {G. H. Ashley},
  year = {1917},
  doi = {10.3133/b641l},
  url = {https://pubs.usgs.gov/publication/b641L},
  note = {Source identifier: b641L}
}