Harun, M. Paul Moses, The Saint and the Sultan: The Crusades, Islam, and Francis of Assisi’s Mission of Peace, New York: Doubleday, 2009, 302 Hlm. : John Tolan, Saint Francis and the Sultan: The Curious History of a Christian-Muslim Encounter, Oxford: Oxford University Press, 2009, Xvi + 382 Hlm. Frank M. Rega, St. Francis of Assisi and the Conversion of the Muslims, Rockford: Ill.: Tan Books, 2007, 125 Hlm. . diskursus 2010, 9, 289-296.