@misc{indiciae44fc306f0e4d,
  title = {Geochemical evidence for suppression of pelagic marine productivity at the Cretaceous/Tertiary boundary},
  author = {James Zachos and M.A. Arthur and Walter E. Dean},
  year = {1989},
  doi = {10.1038/337061a0},
  url = {https://pubs.usgs.gov/publication/70210010},
  note = {Source identifier: 70210010}
}