@misc{indiciae7007c6e42741,
  title = {Geologic map of the Corona South 7.5' quadrangle, Riverside and Orange counties, California},
  author = {C. H. Gray and Douglas M. Morton and F. Harold Weber and Kelly R. Bovard and Timothy O'Brien},
  year = {2002},
  doi = {10.3133/ofr0221},
  url = {https://pubs.usgs.gov/publication/ofr0221},
  note = {Source identifier: ofr0221}
}