A Plane-Symmetric Gravitational Field as a Generalized Nonlinear Sigma   Model
  The Einstein equations for a plane-symmetric gravitational field coupled to an arbitrary nonlinear sigma model (NSM) are shown to be represented in the form of dynamical equations of a {\it generalized effective NSM}. The gravitational equations are studied in this case by the methods of analyzing NSM equations. In the case of a two-component diagonal NSM exact solutions are found by the functional parameter method. 
S.V.Chervon, D.Yu. Shabalkin