Two new sum rules are derived relating Dirac radii and anomalous magnetic
moments of the considered strongly interacting fermions with the convergent
integral over a difference of the total proton and neutron, as well as He3
and H3, photoproduction cross-sections.Comment: 1 eps figure. Contribution presented at the PHOTON'03, April 7-11,
2003, Frascati (Roma), Ital