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Winthrop-Young, Geoffrey (2009). "Fallacies and Thresholds: Notes on the Early Evolution of Alternate History". Historical Social Research. 34 (2 (128)): 99–117. JSTOR20762357.
Holopainen, Toivo J. (2016). "Peter Damian". In Zalta, Edward N. (ed.). The Stanford Encyclopedia of Philosophy (Winter 2016 ed.). Metaphysics Research Lab, Stanford University.
Damian, Pierre (2013) [1998]. Letters of Peter Damian 91-120. The Fathers of the Church. Mediaeval Continuation. Translated by Blum, Owen J. Washington, DC: Catholic University of America Press. pp. 344–386. ISBN978-0813226392. OCLC950930030.
