@misc{indiciae0b8eb1ccc47f,
  title = {Lithologic studies of fine-grained Upper Cretaceous sedimentary rocks of the Black Hills region},
  author = {W.W. Rubey},
  year = {1931},
  doi = {10.3133/pp165a},
  url = {https://pubs.usgs.gov/publication/pp165A},
  note = {Source identifier: pp165A}
}