  A saturating hamiltonian is presented in a relativistically covariant
formalism. The interaction is described by scalar and vector mesons, with
coupling strengths adjusted to the nuclear matter. No explicit density depe
ndence is assumed. The hamiltonian is applied in a QMD calculation to determine
the fragment distribution in O + Br collision at different energies (50 -- 200
MeV/u) to test the applicability of the model at low energies. The results are
compared with experiment and with previous non-relativistic calculations.
  PACS: 25.70Mn, 25.75.+r
