@misc{indiciaeb97be0e6d4c5,
  title = {Mount St. Helens volcanic-ash fall in the Bull Run watershed, Oregon, March-June 1980},
  author = {M.V. Shulters and Daphne G. Clifton},
  year = {1980},
  doi = {10.3133/cir850a},
  url = {https://pubs.usgs.gov/publication/cir850A},
  note = {Source identifier: cir850A}
}