Ginzburg-Landau Expansion in a Toy Model of Superconductor with   Pseudogap
  We propose a toy model of electronic spectrum of two-dimensional system with ``hot-patches'' on the Fermi surface, which leads to essential renormalization of spectral density (pseudogap). Within this model we derive Ginzburg-Landau expansion for both s-wave and d-wave Cooper pairing and analyze the influence of pseudogap formation on the basic properties of superconductors. 
A.I.Posazhennikova, M.V.Sadovskii