Vertex Operators and Soliton Solutions of Affine Toda Model with U(2)   Symmetry
  The symmetry structure of non-abelian affine Toda model based on the coset $SL(3)/SL(2)\otimes U(1)$ is studied. It is shown that the model possess non-abelian Noether symmetry closing into a q-deformed $SL(2)\otimes U(1)$ algebra. Specific two vertex soliton solutions are constructed. 
I. Cabrera-Carnero, J.F. Gomes, G.M. Sotkov and A.H. Zimerman