@misc{indiciae20f6763409a0,
  title = {Assessing U.S. coal resources and reserves},
  author = {Brian N. Shaffer},
  year = {2017},
  doi = {10.3133/fs20173067},
  url = {https://pubs.usgs.gov/publication/fs20173067},
  note = {Source identifier: fs20173067}
}