TY  - RPRT
TI  - A U.S. Geological Survey data standard: Codes for the identification of hydrologic units in the United States and the Caribbean outlying areas
AU  - Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey
PY  - 1982
DO  - 10.3133/cir878a
UR  - https://pubs.usgs.gov/publication/cir878A
ID  - cir878A
ER  -