@misc{indiciae67f1250a2155,
  title = {Ecoregion, land-surface form, and hydrologic unit maps of the U.S},
  author = {Robert G. Bailey and Charles T. Cushwa},
  year = {1982},
  url = {https://pubs.usgs.gov/publication/fwsobs82\_09},
  note = {Source identifier: fwsobs82\_09}
}