@misc{indiciae88f6240a0b23,
  title = {Use of classes based on redox and groundwater age to characterize the susceptibility of principal aquifers to changes in nitrate concentrations, 1991 to 2010},
  author = {P.B. McMahon},
  year = {2012},
  doi = {10.3133/sir20125220},
  url = {https://pubs.usgs.gov/publication/sir20125220},
  note = {Source identifier: sir20125220}
}