@misc{indiciae850fed430c28,
  title = {Geology of the Tucson quadrangle, Arizona},
  author = {S.F. Turner and B.N. Moore and C.F. Tolman and B. S. Butler and R.M. Hernen},
  year = {1949},
  doi = {10.3133/ofr491},
  url = {https://pubs.usgs.gov/publication/ofr491},
  note = {Source identifier: ofr491}
}