@article{ben1997chemomodulation,
  title={Chemomodulation of cellular movement, collective formation of vortices by swarming bacteria, and colonial development},
  author={Ben-Jacob, Eshel and Cohen, Inon and Czir{\'o}k, Andr{\'a}s and Vicsek, Tam{\'a}s and Gutnick, David L},
  journal={Physica A: Statistical Mechanics and its Applications},
  volume={238},
  number={1},
  pages={181--197},
  year={1997},
  publisher={Elsevier}
}