@misc{indiciae2d5e9146d4ea,
  title = {Distribution of selected herbicides and nitrate in the Mississippi River and its major tributaries, April through June 1991},
  author = {D. A. Goolsby and R.C. Coupe and D.J. Markovchick},
  year = {1991},
  doi = {10.3133/wri914163},
  url = {https://pubs.usgs.gov/publication/wri914163},
  note = {Source identifier: wri914163}
}