  We present a detailed study of chemical freeze-out in nucleus-nucleus
collisions at beam energies of 11.6, 30, 40, 80 and 158A GeV. By analyzing
hadronic multiplicities within the statistical hadronization approach, we have
studied the chemical equilibration of the system as a function of center of
mass energy and of the parameters of the source. Additionally, we have tested
and compared different versions of the statistical model, with special emphasis
on possible explanations of the observed strangeness hadronic phase space
under-saturation.
