Behringer, R. P.Geng, JunfeiHowell, D.Longhi, E.Reydellet, G.2004-12-032004-12-0320012001http://hdl.handle.net/2003/54910.17877/DE290R-10330enThe American Physical SocietyPhysical Review Letters530Footprints in Sand: The Response of a Granular Material to Local Perturbations10.1103/PhysRevLett.87.035506article (journal)