@misc{indiciaeca0ce8e912ba,
  title = {Coal quality: Global priorities},
  author = {Brenda S. Pierce and Kristin O. Dennen and Robert B. Finkelman},
  year = {2004},
  doi = {10.3133/cir1272},
  url = {https://pubs.usgs.gov/publication/cir1272},
  note = {Source identifier: cir1272}
}