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