@misc{indiciae9c1f7f84c64e,
  title = {X-ray mineralogy of cores from two Guatemalan caldera lakes},
  author = {Lawrence J. Poppe and Charles K. Paull and Christopher G. Newhall},
  year = {1981},
  doi = {10.3133/ofr811333},
  url = {https://pubs.usgs.gov/publication/ofr811333},
  note = {Source identifier: ofr811333}
}