2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/171972We present a brief review of current methods for the calculation of multi-loop amplitudes including recent developments. As an example we present the calculation of the second moment of the heavy quark current correlator and the extraction of the values of the charm and bottom quark masses using the results of this calculation.Parallel talk at ICHEP08, Philadelphia, USA, July 2008. 4 pages, LaTeXHigh Energy Physics - Phenomenologytext