@misc{indiciae704e6f9c319c,
  title = {Results of spirit leveling in Colorado, 1896 to 1910, inclusive},
  author = {Robert Bradford Marshall},
  year = {1911},
  doi = {10.3133/b486},
  url = {https://pubs.usgs.gov/publication/b486},
  note = {Source identifier: b486}
}