@misc{indiciae80ba961303de,
  title = {Reconnaissance geologic map of parts of the Twin Peaks and Blanca Peak quadrangles, Alamosa, Costilla, and Huerfano counties, Colorado},
  author = {B. R. Johnson and R.M. Bruce},
  year = {1991},
  doi = {10.3133/mf2169},
  url = {https://pubs.usgs.gov/publication/mf2169},
  note = {Source identifier: mf2169}
}