@misc{indiciaecffdbedbcdde,
  title = {Potential nitrogen critical loads for northern Great Plains grassland vegetation},
  author = {Amy J. Symstad and Anine T. Smith and Wesley E. Newton and Alan K. Knapp},
  year = {2015},
  url = {https://pubs.usgs.gov/publication/70155195},
  note = {Source identifier: 70155195}
}