@conference {BBPG97, title = {Introducing the Sphericle: an experimental testbed for research and teaching in nonholonomy}, booktitle = {Proc. IEEE Int. Conf. on Robotics and Automation}, year = {1997}, keywords = {Autonomous Vehicles, Nonlinear Control Systems}, author = {A. Bicchi and A. Balluchi and D Prattichizzo and A. Gorelli} }