@misc{indiciaeee00630b5efa,
  title = {Carbon isotopes in pelites of the Precambrian Uncompahgre Formation, Needle Mountains, Colorado},
  author = {Fred Barker and Irving Friedman},
  year = {1969},
  doi = {10.1130/0016-7606(1969)80[1403:ciipot]2.0.co;2},
  url = {https://pubs.usgs.gov/publication/70223870},
  note = {Source identifier: 70223870}
}