@misc{indiciae59be85a7359c,
  title = {Generalized boundaries of the National Water-Quality Assessment (NAWQA) Study-Unit Investigations in the conterminous United States 1991-2001},
  author = {K.J. Hitt},
  year = {2006},
  doi = {10.3133/70046920},
  url = {https://pubs.usgs.gov/publication/70046920},
  note = {Source identifier: 70046920}
}