@misc{indiciae4c51c52faa04,
  title = {Petroleum exploration plays and resource estimates, 1989, onshore United States; Region 4, Rocky Mountains and Northern Great Plains},
  author = {R. B. Powers},
  year = {1993},
  doi = {10.3133/ofr93337},
  url = {https://pubs.usgs.gov/publication/ofr93337},
  note = {Source identifier: ofr93337}
}