@misc{indiciaeb94dd63c0261,
  title = {Determination of the sources of nitrate contamination in karst springs using isotopic and chemical indicators},
  author = {S.V. Panno and Keith C. Hackley and H.-H. Hwang and W.R. Kelly},
  year = {2001},
  doi = {10.1016/s0009-2541(01)00318-7},
  url = {https://pubs.usgs.gov/publication/70023352},
  note = {Source identifier: 70023352}
}