@misc{indiciaed69c07aade02,
  title = {Preliminary chemical and mineralogical analyses of the major volcanic ash beds in the Oligocene Brule Formation, northwestern Nebraska},
  author = {Kendell A. Dickinson},
  year = {1994},
  doi = {10.3133/ofr94292},
  url = {https://pubs.usgs.gov/publication/ofr94292},
  note = {Source identifier: ofr94292}
}