@misc{indiciae05753a00f230,
  title = {Geologic map of the Black Hills area, South Dakota and Wyoming},
  author = {Ed DeWitt and J. A. Redden and D. P. Buscher and A.B. Wilson},
  year = {1989},
  doi = {10.3133/i1910},
  url = {https://pubs.usgs.gov/publication/i1910},
  note = {Source identifier: i1910}
}