Measurement of Coulomb drag between Anderson insulators
  We report observations of the Coulomb drag effect between two effectively 2-d insulating a-Si_{1-x}Nb_{x} films. We find that there only exist a limited range of experimental parameters over which we can measure a sizable linear-response transresistivity (\rho_{d}). The temperature dependence of \rho_{d} is consistent with the layers being Efros-Shklovskii Anderson insulators provided that a 3-d density of states and a localization length smaller than that obtained from the DC layer-conductivity are assumed. 
K. Elsayad, J. P. Carini, and D. V. Baxter