2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/47383We present a general classification of all four fermion final states in $γγ$~collisions and a calculation of cross sections below the $W^+W^-$-threshold.3 pages, LaTeX, contribution to the proceedings of "The International Europhysics Conference on High-Energy Physics", 19-26 August 1997, Jerusalem, IsraelHigh Energy Physics - Phenomenologytext