TY  - RPRT
TI  - Nitrogen in the environment: sources, problems, and management.
AU  - R F Follett
AU  - J L Hatfield
PY  - 2001
DO  - 10.1100/tsw.2001.269
UR  - https://pubmed.ncbi.nlm.nih.gov/12805892/
ID  - 12805892
ER  -