A New Method of the Corotation Radius Evaluation in our Galaxy
  We propose a new method for determination of the rotation velocity of the
galactic spiral density waves, correspondingly, the corotation radius, $r_C$,
in our Galaxy by means of statistical analysis of radial oxygen distribution in
the galactic disc derived over Cepheids. The corotation resonance happens to be
located at $r_C \sim 7.0 - 7.6 $ kpc, depending on the rate of gas infall on to
the galactic disc, the statistical error being $\sim 0.3 - 0.4$ kpc.
Simultaneously, the constant for the rate of oxygen synthesis in the galactic
disc was determined.
  We also argue in favour of a very short time-scale formation of the galactic
disc, namely: $t_f \sim 2$ Gyr. This scenario enables to solve the problem of
the lack of intergalactic gas infall.
