"Subthreshold" $e^+e^-$ pairs production on photon colliders
  In this paper we consider the process of "subthreshold" electron-positron pairs creation in the region of laser conversion. The total number of positrons and their distribution are obtained. This phenomena is offered for use as a good test to examine nonlinear effects of quantum electrodynamics on TESLA. 
A. A. Kochanov, S. I. Polityko (Irkutsk State University)