@misc{indiciaeaf44cff81a98,
  title = {Methods of analysis by the U. S. Geological Survey National Water Quality Laboratory-Determination of organonitrogen herbicides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring},
  author = {Mark W. Sandstrom and Duane S. Wydoski and Michael P. Schroeder and Jana L. Zamboni and William T. Foreman},
  year = {1992},
  doi = {10.3133/ofr91519},
  url = {https://pubs.usgs.gov/publication/ofr91519},
  note = {Source identifier: ofr91519}
}