@misc{indiciaeec27ee6e660b,
  title = {Calcium-Carbonate hardness of public water supplies in the conterminous United States},
  author = {Barbara M. Anderson},
  year = {1971},
  doi = {10.1130/mem123-p151},
  url = {https://pubs.usgs.gov/publication/70227313},
  note = {Source identifier: 70227313}
}