@misc{indiciaef0f5ae5e1299,
  title = {Slope map of the Aspen Quadrangle, Pitkin County, Colorado},
  author = {Bruce Bryant},
  year = {1972},
  doi = {10.3133/i785e},
  url = {https://pubs.usgs.gov/publication/i785E},
  note = {Source identifier: i785E}
}