  Oscillations of the Dirac neutrinos of three generations in vacuum are
considered with allowance made for the effect of the CP-violating leptonic
phase (analogue of the quark CP phase) in the lepton mixing matrix. The general
formulas for the probabilities of neutrino transition from one sort to another
in oscillations are obtained as functions of three mixing angles and the CP
phase. It is found that the leptonic CP phase can, in principle, be
reconstructed by measuring the oscillation-averaged probabilities of neutrino
transition from one sort to another. The manifestation of the CP phase as a
deviation of the probabilities of direct processes from those of inverse
processes is an effect that is practically unobservable as yet.
