2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42273Different approaches to gluon shadowing at small x are reviewed. Some available results relevant for RHIC and LHC are compared.6 pages, LaTeX2e, uses enclosed cernrep.cls, one eps figure enclosed using graphicx, contribution to the Yellow Report on Hard Probes in Heavy Ion Collisions at the LHCHigh Energy Physics - PhenomenologyGluon distributions in nuclei at small x: guidance from different modelstext