@misc{indiciae6d66396e46e1,
  title = {Thorium and rare-earth minerals in Powderhorn district, Gunnison County, Colorado},
  author = {J. C. Olson and S. R. Wallace},
  year = {1956},
  doi = {10.3133/b1027o},
  url = {https://pubs.usgs.gov/publication/b1027O},
  note = {Source identifier: b1027O}
}