@misc{indiciaef038d0ceea7d,
  title = {Geologic map for land use planning, Prince Georges County, Maryland},
  author = {John Tilton Hack},
  year = {1975},
  doi = {10.3133/ofr75208},
  url = {https://pubs.usgs.gov/publication/ofr75208},
  note = {Source identifier: ofr75208}
}