  A short introduction to the theory of matrix quasiclassical Green's functions
is given and possible applications of this theory to transport properties of
mesoscopic superconducting-normal metal (S/N) structures are considered. We
discuss a simplified version of these equations in the diffusive regime and in
the case of a weak proximity effect. These equations are used for the
calculation of the conductance of different S/N structures. Long-range,
phase-coherent effects are studied in a 4-terminal S/N/S structures under
conditions when the Josephson critical current is negligible. It is shown that
the Josephson effects may be observed in this system if an additional current
flows through the N electrode.
