''After approaching Pope John Paul II with an unidentified object concealed beneath his jacket, Zel'dovich produced a book of his collected papers, which he donated to the Pope. 'Thanks' the Pope replied, to which Zel'dovich loudly responded 'Not just 'thanks'! These are fifty years of my work!'. The Pope kept Zel'dovich's collected papers (Zel'dovich, 1985) under his arm during the entire rest of the audience.''
Ruffini, ''The Ergosphere and Dyadosphere of the Kerr Black Hole'', in Wiltshire et al. (eds), The Kerr Spacetime, p. 79.