TY  - RPRT
TI  - Classification and Mapping of Agricultural Land for National Water-Quality Assessment
AU  - Robert J. Gilliom
AU  - Gail P. Thelin
PY  - 1997
DO  - 10.3133/cir1131
UR  - https://pubs.usgs.gov/publication/cir1131
ID  - cir1131
ER  -