  We study the perturbed Burgers-Korteweg-de Vries equation. This equation can
be used for the description of nonlinear waves in a liquid with gas bubbles and
for the description of nonlinear waves on a fluid layer flowing down an
inclined plane. We investigate the integrability of this equation using the
Painlev\'{e} approach. We show that the perturbed Burgers-Korteweg-de Vries
equation does not belong to the class of integrable equations. Classical and
nonclassical symmetries admitted by this equation and corresponding symmetry
reductions are constructed. New types of periodic analytical structures
described by the Burgers-Korteweg-de Vries equation are found.
