@misc{indiciaecde4c3cafcba,
  title = {The National Coal Resource Assessment Overview},
  author = {Brenda S. Pierce and Kristin O. Dennen},
  year = {2009},
  doi = {10.3133/pp1625f},
  url = {https://pubs.usgs.gov/publication/pp1625F},
  note = {Source identifier: pp1625F}
}