Adams, Byron (2004). "Elgar's later oratorios: Roman Catholicism, decadence and the Wagnerian dialectic of shame and grace". In Grimley, Daniel M.; Rushton, Julian (eds.). The Cambridge Companion to Elgar. Cambridge Companions to Music. Cambridge: Cambridge University Press (published 2005). p. 90. ISBN9781139827089. Retrieved 9 December 2019. Newman clearly modelled the Guardian Angel in Gerontius after Ambrose St John.