1. Vibrating robot showed in Youtube website. Available: http://www.youtube.com/watch?v=EBY-CwlHVoI.
2. Swarming, swirling and stasis in sequestered bristle-bots. Proc. R. Soc;L Giomi;A,2013
3. Petri PA (2001) Vibration-induced rotation. Bachelor in Mechanical Engineering Thesis, MIT, June 2001.
4. Ratchet due to broken friction symmetry. Phys. Rev;B Nordén;E,2001
5. Ratchet device with broken friction symmetry. Appl. Phys. Lett;B Nordén,2002