@misc{indiciae1c40906529bd,
  title = {Aeromagnetic maps of the Twin Buttes area, Pima and Santa Cruz Counties, Arizona, flown at 500 feet above ground and flown at 4,000 feet barometric elevation},
  author = {Gordon E. Andreasen and James A. Pitkin},
  year = {1962},
  doi = {10.3133/ofr624},
  url = {https://pubs.usgs.gov/publication/ofr624},
  note = {Source identifier: ofr624}
}