@misc{indiciae2e0bd837723f,
  title = {Oil and gas resource assessment areas for 1987 assessment, lower 48 states},
  author = {K. L. Varnes and D. L. Dolton and Richard F. Mast},
  year = {1990},
  doi = {10.3133/ofr90614},
  url = {https://pubs.usgs.gov/publication/ofr90614},
  note = {Source identifier: ofr90614}
}