@misc{indiciaee16a31029487,
  title = {Map Database for Surficial Materials in the Conterminous United States},
  author = {David R. Soller and Marith C. Reheis and Christopher P. Garrity and D. R. Van Sistine},
  year = {2009},
  doi = {10.3133/ds425},
  url = {https://pubs.usgs.gov/publication/ds425},
  note = {Source identifier: ds425}
}