Horn, Gerd-Rainer[in Spanish] (2015). The Spirit of Vatican II: Western European Progressive Catholicism in the Long Sixties (1 ed.). Oxford University Press. p. 44. ISBN978-0-19-959325-5.
Horn, Gerd-Rainer[in Spanish] (2015). The Spirit of Vatican II: Western European Progressive Catholicism in the Long Sixties (1 ed.). Oxford University Press. pp. 150–151. ISBN978-0-19-959325-5.