  Qualitatively new transport mechanism is suggested for hopping of carriers
according to which the variable-range hopping (VRH) arises from the resonant
tunneling between transport states brought into resonance by Coulomb potentials
produced by surrounding sites with fluctuating occupations. A semiquantitative
description of the hopping transport is given based on the assumption that
fluctuations of energies of hopping sites have spectral density 1/f.
