@misc{indiciaeaf01f366dd93,
  title = {Reconnaissance geologic map of the Picacho Butte quadrangle, Yavapai and Coconino Counties, Arizona},
  author = {M. H. Krieger},
  year = {1960},
  doi = {10.3133/i500},
  url = {https://pubs.usgs.gov/publication/i500},
  note = {Source identifier: i500}
}