@misc{indiciae171bb12d437f,
  title = {Surficial geology, geomorphology, and erosion of archeologic sites along the Colorado River, eastern Grand Canyon, Grand Canyon National Park, Arizona},
  author = {Richard Hereford and H.C. Fairley and K. S. Thompson and J.R. Balsom},
  year = {1993},
  doi = {10.3133/ofr93517},
  url = {https://pubs.usgs.gov/publication/ofr93517},
  note = {Source identifier: ofr93517}
}