Parametrising the proton structure function
  We show that simple parametrisations at small x of the proton structure function work so well in limited regions of the $(x,Q^2)$ plane because they are approximately "self-consistent" solutions of the QCD evolution equation. For a class of them, we predict their $Q^2$ dependence and compare the result with experimental data. 
L.L. Jenkovszky, A. Lengyel, F. Paccanoni