D. Marion and A. Nur, Percolation of electrical and elastic properties of granular materials at the transition from a suspension to a loose packing, Physica A: Statistical Mechanics and its Applications, vol.157, issue.1, p.575, 1989.
DOI : 10.1016/0378-4371(89)90365-8

C. F. Moukarzel, Isostatic Phase Transition and Instability in Stiff Granular Materials, Physical Review Letters, vol.81, issue.8, p.1634, 1998.
DOI : 10.1103/PhysRevLett.81.1634