@misc{indiciae02194c3a129a,
  title = {Carbonera coal geophysical logging research holes; core descriptions and coal analysis},
  author = {R.G. Hobbs and J. L. Gualtieri and R.N. Babcock},
  year = {1982},
  doi = {10.3133/ofr82827},
  url = {https://pubs.usgs.gov/publication/ofr82827},
  note = {Source identifier: ofr82827}
}