The transformation of Pohlmeyer and $(2+0)$ integrable equations of statistical physics

Using the transformation of Pohlmeyer in euclidean space it obtained the equation, which provide the possibility to construct the wide class of two-dimensional elliptical integrable systems. The question on a gauge equivalence of this systems with nonlinear sigma-model and Getmanov and Bitzadze models is investigated. The exact solution of some equations are constructed.