U(N) Matrix Difference Equations and a Nested Bethe Ansatz
  A system of U(N)-matrix difference equations is solved by means of a nested version of a generalized Bethe Ansatz. The highest weight property of the solutions is proved and some examples of solutions are calculated explicitly. (Part II of a series of articles on the generalized nested Bethe Ansatz and difference equations.) 
H. Babujian, M. Karowski and A. Zapletal