Relativistic form factor in terms of wave functions of composite systems at rest

Using the form-factor calculations as an example, we verify the field-theoretic approach to describing the interaction of composites in terms of wave functions of bound states at rest based on the expansion of the boost operator over the coupling constant powers [1]. It is shown that the taking into account the second order of the perturbation theory is necessary in QGD in order to obtain the leading asymptotics of the meson electromagnetic form-factor at large momentum transfer.