Stochastic dynamics of a sheared granular medium A. Petri, A. Baldassarri, F. Dalton, G. Pontuale, L. Pietronero and S. Zapperi Eur. Phys. J. B, 64 3-4 (2008) 531-535 Published online: 08 May 2008 DOI: 10.1140/epjb/e2008-00177-x