WWF: a generator for e+e- to 4 fermions + gamma
  We present an efficient generator for the process e+e- to 4 fermions + gamma through off-shell W pairs. It is based on a massless matrix element with leading order(m^2) corrections. Only the resonant WW graphs are included. We have tested it against a matrix element without these approximations and found agreement to within ~1% at LEPII energies. 
Geert Jan van Oldenborgh, Paula. J. Franzini and Arianna Borrelli