@misc{indiciae9a226400c941,
  title = {Map showing nonmetallic mineral resources (except fuels) in bedrock, Front Range Urban Corridor, Colorado},
  author = {E. J. Crosby},
  year = {1976},
  doi = {10.3133/i965},
  url = {https://pubs.usgs.gov/publication/i965},
  note = {Source identifier: i965}
}