TY  - RPRT
TI  - Hydrologic Unit Map -- 1974, states of Maryland and Delaware
AU  - Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey
PY  - 1974
DO  - 10.3133/hu20
UR  - https://pubs.usgs.gov/publication/hu20
ID  - hu20
ER  -