@misc{indiciae02da635c3fcf,
  title = {Natural gamma aeroradioactivity map of Bel Air and vicinity, Harford, Baltimore, and Cecil Counties, Maryland},
  author = {R. W. Bromery and A. J. Petty and F. P. Gilbert},
  year = {1964},
  doi = {10.3133/gp484},
  url = {https://pubs.usgs.gov/publication/gp484},
  note = {Source identifier: gp484}
}