@misc{indiciaea1d609985874,
  title = {Economic resources of the northern Black Hills},
  author = {J.D. Irving and S. F. Emmons and T.A. Jaggar},
  year = {1904},
  doi = {10.3133/pp26},
  url = {https://pubs.usgs.gov/publication/pp26},
  note = {Source identifier: pp26}
}