@misc{indiciaef6edb40ed8cc,
  title = {Symposium proceedings; a national agenda for coal-quality research},
  author = {S. P. Schweinfurth},
  year = {1986},
  doi = {10.3133/cir979},
  url = {https://pubs.usgs.gov/publication/cir979},
  note = {Source identifier: cir979}
}