Level Statistics in a Metallic Sample: Corrections to the Wigner-Dyson   Distribution
  Deviation of the level correlation function in a mesoscopic metallic sample from the Wigner--Dyson distribution is calculated by using a combination of the renormalization group and non-perturbative treatment. For given spatial dimension the found correction is determined by the sample conductance. 
Vladimir E. Kravtsov and Alexander D. Mirlin