@misc{indiciaea8a130889485,
  title = {The generation of raster-format geologic maps using digital image-processing on the Macintosh computer; a tutorial guide},
  author = {C.D. Condit and A.V. Acosta},
  year = {1993},
  doi = {10.3133/ofr93526},
  url = {https://pubs.usgs.gov/publication/ofr93526},
  note = {Source identifier: ofr93526}
}