@misc{indiciae9d2a4e1292d1,
  title = {Geologic maps of the Northgate fluorspar district, Colorado},
  author = {Thomas August Steven},
  year = {1951},
  doi = {10.3133/ofr5182},
  url = {https://pubs.usgs.gov/publication/ofr5182},
  note = {Source identifier: ofr5182}
}