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Mandonnet, Pierre: Order of PreachersCatholic Encyclopedia. 1911. New York: Robert Appleton Company. Viitattu 12.4.2010. (englanniksi)
Bihl, Michael: Order of Friars MinorCatholic Encyclopedia. 1911. New York: Robert Appleton Company. Viitattu 12.4.2010. (englanniksi)
stanford.edu
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Sweeney, Eileen: Literary Forms of Medieval PhilosophyThe Stanford Encyclopedia of Philosophy. The Metaphysics Research Lab. Stanford University. Viitattu 12.4.2010. (englanniksi)