@misc{indiciae89f301c0d5c1,
  title = {Principal facts for 1220 gravity stations in Los Angeles 1 degree by 2 degree quadrangle, California},
  author = {William F. Hanna and Robert Sikora},
  year = {1973},
  doi = {10.3133/ofr7399},
  url = {https://pubs.usgs.gov/publication/ofr7399},
  note = {Source identifier: ofr7399}
}