2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/45172We sketch a systematic approach to multiloop calculations. We focus on the Z-factors of a renormalizable theory and show that they can be obtained by purely algebraic methods based on power-counting and the forest structure of the divergent graphs. (submitted contributions to the conference proceedings "Confronting the Infinite", Adelaide February 1994)9 pages, UTAS-PHYS-94-17 (.ps file)High Energy Physics - Phenomenologytext