2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/160775Strong lensing by an isolated spherically symmetric mass distribution is considered in presence of a positive cosmological constant. Deflection angles and time delay are computed and compared to the multiple image of the quasar SDSS J1004+4112.5 pages, 4 figures, Moriond 2008 CosmologyAstrophysicsGeneral Relativity and Quantum Cosmologytext