Perturbative and nonperturbative correlations in double parton   distributions
  We argue that the perturbative QCD correlations contribute dominantly to the double parton distributions as compared to the nonperturbative ones in the limit of sufficiently large hard scales and for not parametrically small longitudinal momentum fractions. 
A.M. Snigirev, N.A. Snigireva, G.M. Zinovjev
hep-ph hep-ex