TY  - RPRT
TI  - Concepts for a National Water-Quality Assessment Program
AU  - Robert M. Hirsch
AU  - William M. Alley
AU  - William G. Wilber
PY  - 1988
DO  - 10.3133/cir1021
UR  - https://pubs.usgs.gov/publication/cir1021
ID  - cir1021
ER  -