@misc{indiciae53f0b5cadfa9,
  title = {Slope maps of the San Francisco Bay region, California: A digital database},
  author = {Scott E. Graham and Richard J. Pike},
  year = {1998},
  doi = {10.3133/ofr98766},
  url = {https://pubs.usgs.gov/publication/ofr98766},
  note = {Source identifier: ofr98766}
}