  Talk given at the "International Workshop on (e,e'p) Processes", July 2-6,
2017, Bled, Slovenia. Various many-body calculations are compared and the
results provided by the Normalization Conserving Linked Cluster Expansion with
realistic NN interactions are reviewed and analyzed in detail, as far as ground
state energies, momentum distributions and spectral functions of few-nucleon
system and complex nuclei are concerned.
