@misc{indiciae5b3aa3e203cc,
  title = {Geologic map of the Silverton and Howardsville quadrangles, southwestern Colorado},
  author = {R. G. Luedke and W. S. Burbank},
  year = {2000},
  doi = {10.3133/i2681},
  url = {https://pubs.usgs.gov/publication/i2681},
  note = {Source identifier: i2681}
}