@misc{indiciaeb950f67ece2e,
  title = {Geochemistry of black shale deposits— A summary report},
  author = {James D. Vine and Elizabeth B. Tourtelot},
  year = {1970},
  doi = {10.2113/gsecongeo.65.3.253},
  url = {https://pubs.usgs.gov/publication/70226292},
  note = {Source identifier: 70226292}
}