  We analyze the applicability of our analytical theory of combination
harmonics in canonical low-dimensional multi-band Fermi liquids, which was
recently criticized by Champel (Phys. Rev. B 65, 153403 (2002)). It is shown
that his claim that our analytical theory does not apply at low temperatures
and in clean samples, is incorrect. We demonstrate that the analytical theory
of combination harmonics is in excellent agreement with the exact numerical
results even at zero temperature and for clean systems, which are the most
challenging for an analytical description.
