2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/111155We recently showed (Class. Quantum Grav.\ 23, 3353; gr-qc/0602091) that aligned Petrov type D purely magnetic perfect fluids are necessarily locally rotationally symmetric (LRS) and hence are all explicitly known. We provide here a more transparent proof.8 pages, no figures. Note on gr-qc/0602091General Relativity and Quantum Cosmologytext