Bemporad, Alberto and Bianchini, Gianni and Brogi, Filippo and Chesi, Graziano Passivity analysis of discrete-time hybrid systems using piecewise polynomial storage functions. In: Decision and Control and European Control Conf. IEEE, 12th-15th December 2005, pp. 5421-5426. ISBN 0-7803-9567-0 (2005)