@misc{indiciaeed839eec76df,
  title = {Digital topographic map of Montgomery County, Maryland},
  author = {J. Nicholas Van Driel},
  year = {1975},
  doi = {10.3133/ofr75420},
  url = {https://pubs.usgs.gov/publication/ofr75420},
  note = {Source identifier: ofr75420}
}