@misc{indiciae6ba2d3d9304c,
  title = {Grayhouse area, Amador County, California},
  author = {G.R. Heyl and M.H. Staatz},
  year = {1946},
  doi = {10.3133/ofr4624},
  url = {https://pubs.usgs.gov/publication/ofr4624},
  note = {Source identifier: ofr4624}
}