@misc{indiciae35d72674c0ae,
  title = {Coal resources of the United States, January 1, 1967},
  author = {Paul Averitt},
  year = {1969},
  doi = {10.3133/b1275},
  url = {https://pubs.usgs.gov/publication/b1275},
  note = {Source identifier: b1275}
}