More on the Burkhardt-Cottingham Sum Rule in QCD
  The QCD higher order effects to the polarized structure function $g_2(x, Q^2 )$ are reanalyzed for massive quarks in the context of the operator product expansion. We confirm that the lowest moment of $g_2 (x, Q^2 )$ which corresponds to the Burkhardt-Cottingham sum rule does {\sl not} suffer from radiative corrections in perturbative QCD. 
Jiro Kodaira, Satoshi Matsuda, Tsuneo Uematsu and Ken Sasaki