Spin-Dependent Structure Function g_1 at Small x
  Accounting for double-logarithms of x and running QCD coupling leads to expressions for both the non-singlet and singlet components of $g_1$. These expressions manifest the Regge asymptotics when x ->0 and differ considerably from the DGLAP expressions at small values of x. 
B. I. Ermolaev, M. Greco and S. I. Troyan