The Weizsacker-Williams Approximation to Trident Production in   Electron-Photon Collisions
  The appears to exist no detailed calculation of the multiphoton trident process e + n omega_0 -> e' + e+e-, which can occur during the interaction of an electron beam with an intense laser beam. We present a calculation in the Weizsacker-Williams approximation that is in good agreement with QED calculations for the weak-field case. 
C. Bula, K.T. McDonald