R. Rosenbaum et al., A USEFUL MOTT-EFROS-SHKLOVSKII-RESISTIVITY CROSSOVER FORMULATION FOR 3-DIMENSIONAL FILMS, Journal of physics. Condensed matter, 9(29), 1997, pp. 6247-6256
Useful and simple 3D crossover expressions are presented for the resis
tance versus temperature behaviour in highly insulating 3D films. At h
igh temperatures, this theory extrapolates to the Mott variable-range
hopping law, and at low temperatures to the Efros-Shklovskii variable-
range hopping law. Good agreement is found between the crossover theor
y and resistance measurements.