@misc{indiciaef6ffc63fe947,
  title = {Report of the U.S. Geological Survey's evaluation program for standard reference samples distributed in April 1993; T-123 (trace constituents), T-125 (trace constituents), M-126 (major constituents, N-38 (nutrients), N-39 (nutrients), P-20 (low ionic strength, and Hg-16 (mercury)},
  author = {H.K. Long and J.W. Farrar},
  year = {1993},
  doi = {10.3133/ofr93436},
  url = {https://pubs.usgs.gov/publication/ofr93436},
  note = {Source identifier: ofr93436}
}