  Spectroscopic factors involving well bound nucleons in light nuclei are
calculated with standard shell model, no-core shell model and Gamow shell
model. Continuum coupling is included exactly in the Gamow shell model, due to
the use of the Berggren basis, which contains bound, resonance and scattering
states. Conversely, it is absent from standard and no-core shell models, where
a basis of harmonic oscillator states is used. As the A - 1 nuclei for which
spectroscopic factors are calculated are either weakly bound or unbound,
coupling to continuum is prominent, even though the A nuclei are well bound. It
is then showed that Gamow shell model can properly reproduce experimental data
and is a predictive tool for detailed nuclear structure at drip-line, contrary
to standard and no-core shell model.
