@misc{indiciaef273333bdc81,
  title = {An evaluation of trends in the acidity of precipitation and the related acidification of surface water in North America},
  author = {John T. Turk},
  year = {1983},
  doi = {10.3133/wsp2249},
  url = {https://pubs.usgs.gov/publication/wsp2249},
  note = {Source identifier: wsp2249}
}