Saturation model for 2-gamma physics
  We introduce a saturation model for photon-photon interactions, based on a QCD dipole picture of high energy scattering. The two-dipole cross-section is assumed to satisfy the saturation property. This pomeron-like contribution is supplemented with QPM and non-pomeron reggeon contributions. The model gives a very good description of the data on the gamma-gamma total cross-section, on the photon structure function F_2^gamma(x,Q^2) at low x and on the gamma*-gamma* cross-section. 
N. Timneanu, J. Kwiecinski, L. Motyka