@misc{indiciae94cd9b1cffe8,
  title = {Bitumen-bearing deposits of the United States},
  author = {Bonnie L. Crysdale and Christopher J. Schenk},
  year = {1988},
  doi = {10.3133/b1784},
  url = {https://pubs.usgs.gov/publication/b1784},
  note = {Source identifier: b1784}
}