@article{small,
  title={Biogenicity of Earth’s earliest fossils: A resolution of the controversy},
  author={Schopf, J. William and Kudryavtsev, Anatoliy B.},
  journal={Gondwana Research},
  volume={22},
  pages={761–771},
  year={2012},
  doi={10.1016/j.gr.2012.07.003}
}