Submodels of Nonlinear Grassmann Sigma Models in Any Dimension and   Conserved Currents, Exact Solutions
  In the preceding paper(hep-th/9806084), we constructed submodels of nonlinear Grassmann sigma models in any dimension and, moreover, an infinite number of conserved currents and a wide class of exact solutions.   In this paper, we first construct almost all conserved currents for the submodels and all ones for the one of ${\bf C}P^1$-model. We next review the Smirnov and Sobolev construction for the equations of ${\bf C}P^1$-submodel and extend the equations, the S-S construction and conserved currents to the higher order ones. 
Kazuyuki Fujii, Yasushi Homma and Tatsuo Suzuki