TY  - RPRT
TI  - County-level estimates of nitrogen and phosphorus fertilizer use in the United States, 1945 to 1985
AU  - Richard B. Alexander
AU  - Richard A. Smith
PY  - 1990
DO  - 10.3133/ofr90130
UR  - https://pubs.usgs.gov/publication/ofr90130
ID  - ofr90130
ER  -