@misc{indiciae7d43469ad18c,
  title = {External quality-assurance results for the National Atmospheric Deposition Program/National Trends Network during 1991},
  author = {M.A. Nilles and J.D. Gordon and L.J. Schroder and C.E. Paulin},
  year = {1995},
  doi = {10.3133/wri934208},
  url = {https://pubs.usgs.gov/publication/wri934208},
  note = {Source identifier: wri934208}
}