TY  - RPRT
TI  - Ecoregion, land-surface form, and hydrologic unit maps of the U.S
AU  - Robert G. Bailey
AU  - Charles T. Cushwa
PY  - 1982
UR  - https://pubs.usgs.gov/publication/fwsobs82_09
ID  - fwsobs82_09
ER  -