@misc{indiciaea9e348c4bf8f,
  title = {Geology of the northern Santa Ana Mountains, California},
  author = {J. E. Schoellhamer and J. G. Vedder and R. F. Yerkes and D.M. Kinney},
  year = {1981},
  doi = {10.3133/pp420d},
  url = {https://pubs.usgs.gov/publication/pp420D},
  note = {Source identifier: pp420D}
}