Zerbi, Piero. San Francesco d'Assisi e la Chiesa romana. IN Zerbi, Piero. Ecclesia in hoc mundo posita. Volume 6 de Bibliotheca erudita. Volume 6 de Fonti e Studi per la Storia dell'Università di Pavia. Vita e Pensiero, 1993. pp. 375-381
Benton, John. Consciousness of Self. IN Benson, Robert Louis et alii. Renaissance and renewal in the twelfth century. Volume 26 de Medieval Academy reprints for teaching. University of Toronto Press, 1991. pp. 282-284
Roest, Bert. Dealing with Brother Ass. IN Mulder-Bakker, Anneke B. The invention of saintliness. Volume 2 de Routledge studies in medieval religion and culture. Routledge, 2002. pp. 168-170
Voegelin, Eric. Saint Francis. IN Von Sivers, Peter (ed). The Collected Works of Eric Voegelin. Vol. XX: History of Political Ideas: The Middle Ages to Aquinas. University of Missouri Press, 1997. pp. 141-143
Bynum, Caroline Walker. Men's use of female symbols. IN Little, Lester K. & Rosenwein, Barbara H. Debating the Middle Ages: issues and readings. Wiley-Blackwell, 1998. pp. 279-283
Manselli, Raoul. Appunti sulla religiosità popolare in Francesco d'Assisi. IN Lievens, R. et alii. Pascua Mediaevalia: studies voor Prof. Dr. J.M. de Smet. Mediaevalia Lovaniensia, Series I, Studia X. Leuven University Press, 1983. pp. 310-311
Blastic, Michael. Prayer in the Writings of Francis. IN Johnson, Timothy J. Franciscans at prayer. Volume 4 de The medieval Franciscans. Brill, 2007. pp. 27-28