@misc{indiciae5c107d5d30b9,
  title = {Aeromagnetic map of the Beltsville quadrangle, Montgomery and Prince Georges Counties, Maryland},
  author = {R. W. Bromery and F. P. Gilbert},
  year = {1963},
  doi = {10.3133/gp399},
  url = {https://pubs.usgs.gov/publication/gp399},
  note = {Source identifier: gp399}
}