TY  - RPRT
TI  - County-level estimates of nitrogen and phosphorus from commercial fertilizer for the Conterminous United States, 1987-2006
AU  - Jo Ann M. Gronberg
AU  - Norman E. Spahr
PY  - 2012
DO  - 10.3133/sir20125207
UR  - https://pubs.usgs.gov/publication/sir20125207
ID  - sir20125207
ER  -