@misc{indiciae73e4b1316bcb,
  title = {Digital line graphs from 1:24,000-scale maps},
  author = {William R. Allder and Atef A. Elassal},
  year = {1984},
  doi = {10.3133/cir895c},
  url = {https://pubs.usgs.gov/publication/cir895C},
  note = {Source identifier: cir895C}
}