Two-Loop Computation of the Schroedinger Functional in Pure SU(3)   Lattice Gauge Theory
  We compute the Schroedinger functional (SF) for the case of pure SU(3) gauge theory at two-loop order in lattice perturbation theory. This allows us to extract the three-loop beta-function in the SF-scheme. These results are required to compute the running coupling, the Lambda-parameter and quark masses by finite size techniques with negligible systematic errors. In addition, we can now implement two-loop O(a) improvement in simulations and extend and study series in alternative ("tadpole-improved") bare couplings. 
A. Bode, P. Weisz and U. Wolff