Brown 2001, p. 572 (Meyerbeer's revisions for Florence, Trieste, Padua, London, and Paris); Huebner 1992 (Paris cast); Letellier 2009 (dates); Loewenberg 1978, col. 692 (Teatro della Pergola, Florence). Brown, Clive (2001). "Giacomo Meyerbeer". In Amanda Holden (ed.). The New Penguin Opera Guide. New York: Penguin Putnam. pp. 570–577. ISBN0-14-029312-4. Huebner, Steven (1992). "Crociato in Egitto, Il". In Stanley Sadie (ed.). The New Grove Dictionary of Opera. Vol. 1. New York: Grove (Oxford University Press). pp. 1015–1017. ISBN978-0-19-522186-2.. Also at Oxford Music Online (subscription required). Letellier, Robert Ignatius (2009). "Introduction". The Meyerbeer Libretti (11 volumes (2004–2009)). Vol. 4. Translated by Richard Arsenty (2nd ed.). Newcastle upon Tyne: Cambridge Scholars. pp. xi–xx. ISBN9781847189714. Loewenberg, Alfred (1978). Annals of Opera 1597–1940 (3rd, revised ed.). Totowa, New Jersey: Rowman and Littlefield. ISBN978-0-87471-851-5.