TY  - RPRT
TI  - Hydrologic Unit Map -- 1974, state of Arkansas
AU  - Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey
PY  - 1977
DO  - 10.3133/hu4
UR  - https://pubs.usgs.gov/publication/hu4
ID  - hu4
ER  -