@misc{indiciaec2cf1658e755,
  title = {Simple Bouguer gravity map of Baltimore County and Baltimore City, Maryland},
  author = {R. W. Bromery},
  year = {1967},
  doi = {10.3133/gp614},
  url = {https://pubs.usgs.gov/publication/gp614},
  note = {Source identifier: gp614}
}