@misc{indiciae207640164a64,
  title = {Natural gamma aeroradioactivity map of the Seneca and part of the Sterling quadrangles; Montgomery County, Maryland, and Loudoun and Fairfax Counties, Virginia},
  author = {Jean Blanchett and Andrew Griscom and J. L. Vargo},
  year = {1966},
  doi = {10.3133/gp564},
  url = {https://pubs.usgs.gov/publication/gp564},
  note = {Source identifier: gp564}
}