  We study the localization properties of disordered d-wave superconductors by
means of the fermionic replica trick method. We derive the effective non-linear
sigma-model describing the diffusive modes related to spin transport which we
analyze by the Wilson-Polyakov renormalization group. A lot of different
symmetry classes are considered within the same framework. According to the
presence or the absence of certain symmetries, we provide a detailed
classification for the behavior of some physical quantities, like the density
of states, the spin and the quasiparticle charge conductivities. Following the
original Finkel'stein approach, we finally extend the effective functional
method to include residual quasiparticle interactions, at all orders in the
scattering amplitudes. We consider both the superconducting and the normal
phase, with and without chiral symmetry, which occurs in the so called
two-sublattice models.
