@misc{indiciae75170de9da53,
  title = {External quality-assurance results for the National Atmospheric Deposition Program and the National Trends Network during 1987},
  author = {R.B. See and L.J. Schroder and T. C. Willoughby},
  year = {1989},
  doi = {10.3133/wri894015},
  url = {https://pubs.usgs.gov/publication/wri894015},
  note = {Source identifier: wri894015}
}