The Chiral Lagrangian Approach to the Non-universal Effects in the Zbb   Vertex
  We calculate the top quark loop corrections to the Zbb vertex in the chiral lagrangian of the dynamical electroweak symmetry breaking theory. We use the effective lagrangian based on coset space SU(2) X U(1) / U(1) with the gauge interactions switched off, so these corrections are directly related to the Physics associated with the heavy top quark and the mass generation in the dynamical models. 
X. Zhang