@misc{indiciae1804cb8ad9af,
  title = {Geologic mapping of tunnels using photogrammetry--control-point configuration},
  author = {Jeffrey A. Coe and Keld S. Dueholm},
  year = {1991},
  doi = {10.3133/ofr9037},
  url = {https://pubs.usgs.gov/publication/ofr9037},
  note = {Source identifier: ofr9037}
}