2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/132622This paper has mainly a pedagogical meaning. Our aim is to demonstrate a correct general approach for constructing indicative surfaces of higher-rank tensors. We reconstruct the surfaces of piezo-optic tensor for beta-BaB2O4 and LiNbO3 crystals, which have been incorrectly presented in our recent papers.7 pages, 5 figuresOpticsGeneral Physicstext