  Relations between differential cross section for inelastic scattering of
electrons on hadrons and hadron form factors (sum rules) are derived on the
basis of analytical properties of heavy photon forward Compton scattering on
hadrons. Sum rules relating the slope of form-factors at zero momentum transfer
and anomalous magnetic moments of hadrons with some integrals on
photo-production on a hadrons is obtained as well. To provide the convergence
of these integrals we construct differences of individual sum rules for
different hadrons. Universal interaction of Pomeron with nucleons is assumed.
We derive the explicit formulae for processes of electro-production on proton
and light isobar nuclei. Sudakov's parametrization of momenta, for peripheral
kinematics relevant here, is used. The light-cone form of differential cross
sections is also discussed. The accuracy of sum rules estimated in frames of
point-like hadrons and it is shown to be at the level of precision achievable
by experiments. Suggestions and predictions for future experiments are also
given.
