@misc{indiciaee9bcc71774e1,
  title = {A digital version of the 1970 U.S. Geological Survey topographic map of the San Francisco Bay region, three sheets, 1:125,000},
  author = {Douglas S. Aitken},
  year = {1997},
  doi = {10.3133/ofr97500},
  url = {https://pubs.usgs.gov/publication/ofr97500},
  note = {Source identifier: ofr97500}
}