On the Asymptotic Behaviour of F_2(x,Q^2)
  We discuss how the proton structure function F2 is described in the HERA kinematic range by double asymptotic expressions for low x and large Q^2. From a NLO double asymptotic approximation of recent data from the H1 experiment at HERA we extract the strong coupling constant alpha_S(M^2_Z)=0.113+/-0.002(stat)+/-0.007(syst). The additional theoretical error can be as large as 0.007. 
A.DeRoeck, M.Klein and Th.Naumann