Excited states of bosons and fermions in a four-Fermi quantum field theory: P. Furlan. International School for Advanced Studies (SISSA), Trieste, Italy, Istituto di Fisica Teorica dell'Universita' di Trieste, Italy and Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Italy; and R. Ra̧czka. International School for Advanced Studies (SISSA), Trieste, Italy and Institute of Nuclear Research, Warsaw, Poland