t tbar Production via Vector Boson Fusion at High Energy e^+ e^-   Colliders
  We examine t tbar production via vector boson fusion at high energy e^+ e^- colliders using the effective vector-boson approximation. We show cross sections as functions of CM energy for various Higgs masses ranging from 100 GeV up to 1 TeV, and also for M_H = infinity which corresponds to the LET. We give expressions for sigma(V_i V_j -> t tbar) in the 2M_(W,Z)/sqrt(s) = 0 approximation and show how this approximation effects the results. 
Mikulas Gintner and Stephen Godfrey