@misc{indiciae4c719ece2c64,
  title = {Terpenoid marker compounds derived from biogenic precursors in volcanic ash from Mount St. Helens, Washington},
  author = {W. E. Pereira and Colleen E. Rostad},
  year = {1983},
  doi = {10.1016/0016-7037(83)90052-2},
  url = {https://pubs.usgs.gov/publication/70012118},
  note = {Source identifier: 70012118}
}