L.  Greco, Gaeta, M., and Piccoli, B., ?Deployment of sensors in a network-like environment?, in Proc. 47th IEEE Conference on Decision and Control, Cancun, Mexico, 2008, pp. 4257?4262. 

A.  Bicchi, Marigo, A., and Piccoli, B., ?Discrete and Hybrid Nonholonomy?, in Hybrid Systems: Computation and Control, 2004, vol. 2993, pp. 157-172.