@misc{indiciaeec587da52a3f,
  title = {Petroleum geology of the Devonian and Mississippian black shale of eastern North America},
  author = {Roy Clark Kepferle},
  year = {1993},
  doi = {10.3133/b1909},
  url = {https://pubs.usgs.gov/publication/b1909},
  note = {Source identifier: b1909}
}