@misc{indiciae67fbc3a9857a,
  title = {Maps for America: cartographic products of the U.S. Geological Survey and others},
  author = {Morris M. Thompson},
  year = {1981},
  doi = {10.3133/70039239},
  url = {https://pubs.usgs.gov/publication/70039239},
  note = {Source identifier: 70039239}
}