@misc{indiciae6d87bfd3fcbe,
  title = {A scientifically based nationwide assessment of groundwater quality in the United States},
  author = {W.M. Alley and P. Cohen},
  year = {1991},
  doi = {10.1007/bf01716071},
  url = {https://pubs.usgs.gov/publication/70016795},
  note = {Source identifier: 70016795}
}