@misc{indiciae701a94bc744a,
  title = {Preliminary report on solid bitumens in Eocene rocks of Piceance Creek basin, northwestern Colorado},
  author = {R. B. O'Sullivan and T.G. Ging},
  year = {1987},
  doi = {10.3133/ofr87478},
  url = {https://pubs.usgs.gov/publication/ofr87478},
  note = {Source identifier: ofr87478}
}