@misc{indiciaeb9254814dc58,
  title = {Geochemical data for Colorado soils: Results from the 2006 state-scale geochemical survey},
  author = {David B. Smith and Karl J. Ellefsen and James E. Kilburn},
  year = {2010},
  doi = {10.3133/ds520},
  url = {https://pubs.usgs.gov/publication/ds520},
  note = {Source identifier: ds520}
}