@misc{indiciae956e059ad0bc,
  title = {Geology and coal deposits of the Dugger quadrangle, Sullivan County, Indiana},
  author = {Frank Edward Kottlowski},
  year = {1954},
  doi = {10.3133/coal11},
  url = {https://pubs.usgs.gov/publication/coal11},
  note = {Source identifier: coal11}
}