@misc{indiciaeffea6a1140ca,
  title = {Aeromagnetic map of the Twin Buttes area, Pima and Santa Cruz Counties, Arizona},
  author = {G. E. Andreasen and J. A. Pitkin},
  year = {1963},
  doi = {10.3133/gp426},
  url = {https://pubs.usgs.gov/publication/gp426},
  note = {Source identifier: gp426}
}