@misc{indiciae2408220fe3e6,
  title = {Abundance and distribution of thorium in the carbonatite stock at Iron Hill, Powderhorn district, Gunnison County, Colorado},
  author = {T.J. Armbrustmacher},
  year = {1980},
  doi = {10.3133/pp1049b},
  url = {https://pubs.usgs.gov/publication/pp1049B},
  note = {Source identifier: pp1049B}
}