Effective QCD Partition Function in Sectors with Non-Zero Topological   Charge and Itzykson-Zuber Type Integral
  It was conjectured by Jackson et.al. that the finite volume effective partition function of QCD with the topological charge $M-N$ coincides with the Itzyskon-Zuber type integral for $M\times N$ rectangular matrices. In the present article we give a proof of this conjecture, in which the original Itzykson-Zuber integral is utilized. 
Toshinao Akuzawa and Miki Wadati