@misc{indiciaec014734056a0,
  title = {Miscellaneous analyses of coal samples from various fields of the United States},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1913},
  doi = {10.3133/b531m},
  url = {https://pubs.usgs.gov/publication/b531M},
  note = {Source identifier: b531M}
}