  The main assumption of the model is that in soft processes mesons behave like
systems made of valence quarks and an effective vacuum- like field. The
4-momentum of the latter represents the relativistic generalization of the
potential energy. The electromagnetic form factors are expressed in terms of
the overlap integral of the initial and final wave functions written under the
form of Lorentz covariant distribution of quark momenta. The calculation is
fully Lorentz covariant and the form factors of the charged mesons are
normalized to unity at t=0.
