@misc{indiciaeef89337ac58f,
  title = {Chemistry of the subalkalic silicic obsidians},
  author = {Ray MacDonald and Robert L. Smith and John E. Thomas},
  year = {1992},
  doi = {10.3133/pp1523},
  url = {https://pubs.usgs.gov/publication/pp1523},
  note = {Source identifier: pp1523}
}