@misc{indiciae2f1a22ed6d16,
  title = {Chemical analyses of coal, coal-associated rocks and coal combustion products collected for the National Coal Quality Inventory},
  author = {Joseph R. Hatch and John H. Bullock and Robert B. Finkelman},
  year = {2006},
  doi = {10.3133/ofr20061162},
  url = {https://pubs.usgs.gov/publication/ofr20061162},
  note = {Source identifier: ofr20061162}
}