@misc{indiciae6c1eb57d4c2f,
  title = {Isopach, structure contour, and resource maps of the R-6 oil-shale zone, Green River Formation, Piceance Creek basin, Colorado},
  author = {Janet K. Pitman},
  year = {1979},
  doi = {10.3133/mf1069},
  url = {https://pubs.usgs.gov/publication/mf1069},
  note = {Source identifier: mf1069}
}