Two-loop heavy top effects on the MZ-MW interdependence
  The O(alpha^2 mt^2/mw^2) correction to the relation between G_\mu and the vector boson masses is computed in the MSbar scheme, and the results are used to investigate the magnitude of the effect on the theoretical prediction of mw and sin^2\theta_\msbar(mz) from alpha, G_\mu, and mz. 
G. Degrassi (1), P. Gambino (2), A. Vicini (1), ((1) Padova, (2) Max   Planck Munich)