@misc{indiciaefcc7ececf506,
  title = {Geology and coal deposits of the Terre Haute and Dennison quadrangles, Vigo County, Indiana},
  author = {Samuel A. Friedman},
  year = {1961},
  doi = {10.3133/coal44},
  url = {https://pubs.usgs.gov/publication/coal44},
  note = {Source identifier: coal44}
}