@misc{indiciae3bf58e628ac5,
  title = {Reconnaissance map showing relative amounts of soil and bedrock in the mountainous part of the Boulder Quadrangle, Boulder County, Colorado},
  author = {P. W. Schmidt and K. L. Pierce},
  year = {1978},
  doi = {10.3133/mf993},
  url = {https://pubs.usgs.gov/publication/mf993},
  note = {Source identifier: mf993}
}