@misc{indiciaedea5c850f8f8,
  title = {Calculation of coal resources using ARC/INFO and Earth Vision; methodology for the National Coal Resource Assessment},
  author = {L.N. Roberts and L.R. Biewick},
  year = {1999},
  doi = {10.3133/ofr995},
  url = {https://pubs.usgs.gov/publication/ofr995},
  note = {Source identifier: ofr995}
}