Large contribution of virtual Delbrück scattering to the emission of photons by relativistic nuclei in nucleus–nucleus and electron–nucleus collisionsI.F. Ginzburg, U.D. Jentschura and V.G. SerboEur. Phys. J. C, 54 2 (2008) 267-276DOI: https://doi.org/10.1140/epjc/s10052-008-0523-8