@misc{indiciaeb13bdda2e6a6,
  title = {Mercury in U.S. coal},
  author = {Robert B. Finkelman and Susan J. Tewalt},
  year = {1998},
  doi = {10.3133/ofr98772},
  url = {https://pubs.usgs.gov/publication/ofr98772},
  note = {Source identifier: ofr98772}
}