  The renormalization of the third moment of the twist-2 flavour non-singlet
Wilson operator is given to two loops in the RI'/SMOM renormalization scheme.
This involves renormalizing the operator itself and the two total derivative
operators into which it mixes by inserting it into a quark 2-point function and
evaluating the amplitudes at the symmetric subtraction point. The corresponding
two loop conversion functions are derived from which the three loop Landau
gauge anomalous dimension is deduced. The full set of amplitudes for the two
loop Green's function for each of the operators are given in both the MSbar and
RI'/SMOM schemes.
