@misc{indiciaee1aaf8267625,
  title = {National geochemical data base: National uranium resource evaluation data for the conterminous United States},
  author = {J. D. Hoffman and Kim P. Buttleman and Russell A. MAPPER display software by Ambroziak and Christine A. MAPPER documentation by Cook},
  year = {1994},
  doi = {10.3133/ds18a},
  url = {https://pubs.usgs.gov/publication/ds18A},
  note = {Source identifier: ds18A}
}