@misc{indiciae24e148fd0748,
  title = {Historical review of and current progress in coal-resource estimation in the United States},
  author = {G.H. Wood},
  year = {1981},
  doi = {10.1130/0016-7606(1981)92<520:hroacp>2.0.co;2},
  url = {https://pubs.usgs.gov/publication/70011900},
  note = {Source identifier: 70011900}
}