@misc{indiciaef1132cc314ba,
  title = {Preliminary geologic map of the Empire Mountains Quadrangle, Pima County, Arizona},
  author = {T.L. Finnell},
  year = {1971},
  doi = {10.3133/ofr71106},
  url = {https://pubs.usgs.gov/publication/ofr71106},
  note = {Source identifier: ofr71106}
}