2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/132250The theory of perturbations of spherically symmetric self-similar black holes is presented, in the Newman-Penrose formalism. It is shown that the wave equations for gravitational, electromagnetic, and scalar waves are separable, though not decoupled. A generalization of the Teukolsky equation is given. Monopole and dipole modes are treated. The Newman-Penrose wave equations governing polar and axial spin-0 perturbations are explored.63 pages, 1 eps figureGeneral Relativity and Quantum CosmologyAstrophysicstext