@misc{indiciae915d9828e44e,
  title = {Hydraulic map of Bright Angel Rapids, Grand Canyon, Arizona},
  author = {S. W. Kieffer},
  year = {1988},
  doi = {10.3133/i1897d},
  url = {https://pubs.usgs.gov/publication/i1897D},
  note = {Source identifier: i1897D}
}