@misc{indiciaee8bc2e386a80,
  title = {Geologic and biostratigraphic framework of the non-marine Cretaceous-Tertiary boundary interval in western North America},
  author = {D. J. Nichols},
  year = {1990},
  doi = {10.1016/0034-6667(90)90058-q},
  url = {https://pubs.usgs.gov/publication/70016048},
  note = {Source identifier: 70016048}
}