@misc{indiciaecbf5f0068a59,
  title = {Coal fields and federal lands of the conterminous United States},
  author = {Laura Biewick},
  year = {1997},
  doi = {10.3133/ofr97461},
  url = {https://pubs.usgs.gov/publication/ofr97461},
  note = {Source identifier: ofr97461}
}