Non-perturbative renormalisation of four fermion operators and B-bar B   mixing with Wilson fermions
  We present new results for the renormalisation and subtraction constants for the four fermion Delta F=2 operators, computed non-perturbatively in the RI-MOM scheme (in the Landau gauge). From our preliminary analysis of the lattice data at beta=6.45, for the B-bar B mixing bag-parameter we obtain B_B^{RGI} = 1.46(7)(1). 
D. Becirevic, V. Gimenez, V. Lubicz, G. Martinelli, M. Papinutto, J.   Reyes