@misc{indiciaef6894d258a43,
  title = {Geology of the western part of the Harold D. Roberts Tunnel, Colorado (Stations 0+00 to 690+00)},
  author = {Ernest Eugene Wahlstrom and Charles Sherwood Robinson and V. Quentin Hornback},
  year = {1981},
  doi = {10.3133/pp831c},
  url = {https://pubs.usgs.gov/publication/pp831C},
  note = {Source identifier: pp831C}
}