@misc{indiciae79d4386b5344,
  title = {PACER; data entry, retrieval, and update for the National Coal Resources Data System (Phase I)},
  author = {Simon M. Cargill and A.C. Olson and A.L. Medlin and M.D. Carter},
  year = {1976},
  doi = {10.3133/pp978},
  url = {https://pubs.usgs.gov/publication/pp978},
  note = {Source identifier: pp978}
}