  We study inhomogeneous multidimensional cosmological models with a higher
dimensional space-time manifold under dimensional reduction. Stability due to
different types of effective potentials is analyzed for specific configurations
of internal spaces. Necessary restrictions on the parameters of the models are
found and masses of gravitational excitons (small inhomogeneous excitations of
the scale factors of the internal spaces near minima of effective potentials)
are calculated.
