@misc{indiciae57c18b5c9395,
  title = {Aeromagnetic map of the Denver area, Colorado},
  author = {J. L. Vargo and F. C. Smith and A. J. Petty},
  year = {1966},
  doi = {10.3133/gp557},
  url = {https://pubs.usgs.gov/publication/gp557},
  note = {Source identifier: gp557}
}