@misc{indiciaea1672d4645e7,
  title = {A study of trends in total phosphorus measurements at NASQAN stations},
  author = {Richard A. Smith and Robert M. Hirsch and James Richard Slack},
  year = {1982},
  doi = {10.3133/wsp2190},
  url = {https://pubs.usgs.gov/publication/wsp2190},
  note = {Source identifier: wsp2190}
}