  The elliptic flow (squeeze-out) of neutrons, protons and light complex
particles in reactions of neutron-rich systems at relativistic energies is
proposed as an observable sensitive to the strength of the symmetry term in the
equation of state at supra-normal densities. Preliminary results from a study
of the existing FOPI/LAND data for 197Au + 197Au collisions at 400 A MeV with
the UrQMD model favor a moderately soft symmetry term with a density dependence
of the potential term proportional to (rho/rho_0)^gamma with gamma = 0.6+-0.3.
