@misc{indiciae64f90c3f2646,
  title = {Geologic map of the Bonanza NE Quadrangle, Chaffee and Saguache counties, Colorado},
  author = {Ralph Erskine Van Alstine},
  year = {1975},
  doi = {10.3133/ofr7553},
  url = {https://pubs.usgs.gov/publication/ofr7553},
  note = {Source identifier: ofr7553}
}