2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/173433The results of an Amplitude Analysis of the world data on integrated and differential cross-sections on $γγ\toππ$ are presented, following the publication of the Belle charged pion results.5 pages, 7 figures. To appear in the Proceedings of the International Workshop on $e^+e^-$ collisions from $ϕ$ to $ψ$, Frascati, April 2008. This version rewords the reference to the work of Achasov and Shestakov, with apologies to them for any misunderstandingHigh Energy Physics - Phenomenologytext