Generalized BFT Formalism of Electroweak Theory in the Unitary Gauge
  We systematically embed the SU(2)$\times$U(1) Higgs model in the unitary gauge into a fully gauge-invariant theory by following the generalized BFT formalism. We also suggest a novel path to get a first-class Lagrangian directly from the original second-class one using the BFT fields. 
Yong-Wan Kim, Young-Jai Park and Sean J. Yoon