@misc{indiciaefa3d02290aa8,
  title = {Geologic excursions through the Sonoran Desert Region, Arizona and Sonora},
  author = {George E. Gehrels and Jon E. Spencer},
  year = {1990},
  url = {https://pubs.usgs.gov/publication/70147539},
  note = {Source identifier: 70147539}
}