  Nonlinear waves are studied in a mixture of liquid and gas bubbles. Influence
of viscosity and heat transfer is taken into consideration on propagation of
the pressure waves. Nonlinear evolution equations of the second and the third
order for describing nonlinear waves in gas-liquid mixtures are derived. Exact
solutions of these nonlinear evolution equations are found. Properties of
nonlinear waves in a liquid with gas bubbles are discussed.
