@misc{indiciae96cc5823d76c,
  title = {Comet showers as a cause of mass extinctions},
  author = {Piet Hut and Walter Alvarez and William P. Elder and Thor Hansen and Erle G. Kauffman and Gerta Keller and Eugene Merle Shoemaker and Paul R. Weissman},
  year = {1987},
  doi = {10.1038/329118a0},
  url = {https://pubs.usgs.gov/publication/70227580},
  note = {Source identifier: 70227580}
}