TY  - RPRT
TI  - Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory-Determination of ammonium plus organic nitrogen by a Kjeldahl digestion method and an automated photometric finish that includes digest cleanup by gas diffusion
AU  - Charles J. Patton
AU  - Earl P. Truitt
PY  - 2000
DO  - 10.3133/ofr00170
UR  - https://pubs.usgs.gov/publication/ofr00170
ID  - ofr00170
ER  -