@misc{indiciae0c8f43f39768,
  title = {Copper deposits of part of Helvetia mining district, Pima County, Arizona},
  author = {S. C. Creasey and G.L. Quick},
  year = {1955},
  doi = {10.3133/b1027f},
  url = {https://pubs.usgs.gov/publication/b1027F},
  note = {Source identifier: b1027F}
}