  For general nonlinear autonomous systems, a Lyapunov characterization for the
possibility of semi-global asymptotic stabilizability by means of a
time-varying sampled-data feedback is established. We exploit this result in
order to derive a Lie algebraic sufficient condition for sampled-data feedback
semi-global stabilizability of affine in the control nonlinear systems with
non-zero drift terms. The corresponding proposition constitutes an extension of
the "Artstein-Sontag" theorem on feedback stabilization.
