@misc{indiciaec8467efbc11a,
  title = {Geology and mineral resources of the western part of the Arkansas coal field},
  author = {T. A. Hendricks and Bryan Parks},
  year = {1937},
  doi = {10.3133/b847e},
  url = {https://pubs.usgs.gov/publication/b847E},
  note = {Source identifier: b847E}
}