Production of two electron-positron couples in electroweak gamma gamma -   interaction
  We present the calculation of gamma gamma -> 2e+e- process cross section. The construction are perfomed using both helicity amplitude method and method of precision covariant calculation. The magnitude of cross section is obtained by the Monte-Carlo method of numerical integration. Different energies, polarization states and kinematics cuts are considered. 
T.Shishkina, I.Sotsky