@misc{indiciae90f40da97fd8,
  title = {Principal facts for more than 700 new gravity stations in the San Francisco North and San Francisco South quadrangles, California},
  author = {C. W. Roberts},
  year = {1991},
  doi = {10.3133/ofr91103},
  url = {https://pubs.usgs.gov/publication/ofr91103},
  note = {Source identifier: ofr91103}
}