@misc{indiciaeb9734149b228,
  title = {Carbon isotope systematics and CO2 sources in The Geysers-Clear Lake region, northern California, USA},
  author = {D. Bergfeld and F. Goff and C. J. Janik},
  year = {2001},
  doi = {10.1016/s0375-6505(00)00051-1},
  url = {https://pubs.usgs.gov/publication/70023658},
  note = {Source identifier: 70023658}
}