@misc{indiciaeb37f667e68ef,
  title = {Ages of travertine deposits in eastern Grand Canyon National Park, Arizona},
  author = {Barney J. Szabo},
  year = {2017},
  doi = {10.1016/0033-5894(90)90070-2},
  url = {https://pubs.usgs.gov/publication/70016360},
  note = {Source identifier: 70016360}
}