@misc{indiciae02b98073e064,
  title = {Digital line graphs from 1:24,000-scale maps},
  author = {U.S. Geological Survey National Mapping Division},
  year = {1990},
  doi = {10.3133/70047459},
  url = {https://pubs.usgs.gov/publication/70047459},
  note = {Source identifier: 70047459}
}