@misc{indiciaed34806e3a354,
  title = {Analysis of ten coal samples from the Michigan basin},
  author = {Charles L. Oman and Robert B. Finkelman and Ronald T. Talley},
  year = {1992},
  doi = {10.3133/ofr92180},
  url = {https://pubs.usgs.gov/publication/ofr92180},
  note = {Source identifier: ofr92180}
}