The structure of real and virtual photons has been studied in electron-proton
scattering processes producing di-jet events at HERA by the H1 and ZEUS
collaborations. Data have been compared to next-to-leading order QCD
calculations and to the predictions of Monte Carlo generators based on the
DGLAP and CCFM formalisms for describing the parton dynamicsComment: Proceedings 'QCD and High Energy Hadronic Interactions', Recontres de
Morion
