@misc{indiciae4c99636f665d,
  title = {Compilation of historical water-quality data for selected springs in Texas, by ecoregion},
  author = {Franklin T. Heitmuller and Iona P. Williams},
  year = {2006},
  doi = {10.3133/ds230},
  url = {https://pubs.usgs.gov/publication/ds230},
  note = {Source identifier: ds230}
}