  We analyze the features of the graphene mono- and multilayer reflectance in
the far-infrared region as a function of frequency, temperature, and carrier
density taking the intraband conductance and the interband electron absorbtion
into account. The dispersion of plasmon mode of the multilayers is calculated
using Maxwell's equations with the influence of retardation included. At low
temperatures and high electron densities, the reflectance of multilayers as a
function of frequency has the sharp downfall and the subsequent deep well due
to the threshold of electron interband absorbtion.
