Replica Method for Wide Correlators in Gaussian Orthogonal, Unitary And   Symplectic Random Matrix Ensembles
  We calculate connected correlators in Gaussian orthogonal, unitary and symplectic random matrix ensembles by the replica method in the 1/N-expansion. We obtain averaged one-point Green's functions up to the next-to-leading order O(1/N) and wide two-level correlators up to the first nontrivial order O(1/N^2) and wide three-level correlators up to the first nontrivial order $O(1/N^4)$ by carefully treating fluctuations in saddle-point evaluation. 
Chigak Itoi, Hisamitsu Mukaida and Yoshinori Sakamoto