@misc{indiciae243a9bc4a8dd,
  title = {Report on the U.S. Geological Survey's evaluation program for standard reference samples distributed in April 1996 : T-139 (trace constituents), T-141 (trace constituents), M-138 (trace constituents), N-49 (nutrient constituents), N-50 (nutrient constituents), P-26 (low ionic strength constituents) and Hg-22 (Mercury)},
  author = {J.W. Farrar and H.K. Long},
  year = {1996},
  doi = {10.3133/ofr96436},
  url = {https://pubs.usgs.gov/publication/ofr96436},
  note = {Source identifier: ofr96436}
}