@article{small,
  title={Multiple Generations of Carbon in the Apex Chert and Implications forPreservation of Microfossils},
  author={Marshall, Alison Olcott and Emry, Julienne R. and Marshall, Craig P.},
  journal={Astrobiology},
  volume={12},
  pages={160–166},
  year={2012},
  doi={10.1089/ast.2011.0729}
}