@misc{indiciaed93e46739ad2,
  title = {Annotated orthophoto map, 1970, Washington urban area, D.C., Md. and Va.},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1973},
  doi = {10.3133/i858b},
  url = {https://pubs.usgs.gov/publication/i858B},
  note = {Source identifier: i858B}
}