Proof of the Equivalence Theorem in the Chiral Lagrangian Formalism
  A general proof of the equivalence theorem in electroweak theories with the symmetry breaking sector described by the chiral Lagrangian is given in the $R_{\xi}$ gauge by means of the Ward-Takahashi identities. The precise form of the theorem contains a modification factor $C_{mod}$ associated with each external Goldstone boson similar to that in the standard model. $C_{mod}$ is exactly unity in our previously proposed renormalization scheme, {\it Scheme-II}. 
Hong-Jian He, Yu-Ping Kuang, Xiaoyuan Li