@misc{indiciae9bb08426d4da,
  title = {Use of stable isotopes of carbon, nitrogen, and sulfur to identify sources of nitrogen in surface waters in the lower Susquehanna River basin, Pennsylvania},
  author = {Charles A. Cravotta},
  year = {2002},
  doi = {10.3133/wsp2497},
  url = {https://pubs.usgs.gov/publication/wsp2497},
  note = {Source identifier: wsp2497}
}