SU(N) Matrix Difference Equations and a Nested Bethe Ansatz
  A system of SU(N)-matrix difference equations is solved by means of a nested version of a generalized Bethe Ansatz, also called "off shell" Bethe Ansatz. The highest weight property of the solutions is proved. (Part I of a series of articles on the generalized nested Bethe Ansatz and difference equations.) 
H. Babujian, M. Karowski and A. Zapletal