@misc{indiciaed6581beb78e9,
  title = {Aeromagnetic map of the northeastern United States: In color},
  author = {Isidore Zietz and F. P. Gilbert},
  year = {1981},
  doi = {10.3133/gp942},
  url = {https://pubs.usgs.gov/publication/gp942},
  note = {Source identifier: gp942}
}