Asymptotic scaling corrections in QCD with Wilson fermions from the   3-loop average plaquette
  We calculate the 3-loop perturbative expansion of the average plaquette in lattice QCD with N_f massive Wilson fermions and gauge group SU(N). The corrections to asymptotic scaling in the corresponding energy scheme are also evaluated. We have also improved the accuracy of the already known pure gluonic results at 2 and 3 loops. 
B. Alles, A. Feo, H. Panagopoulos