Luxemburg-Gorky effect in a granular medium: Probing perturbations of the material state via cross-modulation of elastic wavesV. Yu. Zaitsev, V. E. Nazarov, V. Tournat, V. E. Gusev and B. CastagnèdeEurophys. Lett., 70 5 (2005) 607-613DOI: https://doi.org/10.1209/epl/i2005-10023-5