Double distributions for the proton
  We derive double distributions for the proton in a simple model that contains scalar as well as axial-vector diquark correlations. The model parameters are tuned so that the experimentally measured electromagnetic form factors are reproduced for small momentum transfer. Resulting generalized parton distributions satisfy known constraints, including the positivity bounds. 
B. C. Tiburzi, W. Detmold, G. A. Miller