@misc{indiciaeadc9bca05336,
  title = {Use of stable isotopes of carbon, nitrogen, and sulfer to identify sources of nitrogen in surface waters in the Lower Susquehanna River basin, Pennsylvania},
  author = {C.A. Cravotta},
  year = {1995},
  doi = {10.3133/ofr94510},
  url = {https://pubs.usgs.gov/publication/ofr94510},
  note = {Source identifier: ofr94510}
}