St. Anselm's Proslogion with a reply on behalf of the Fool by Gaunilo and the author's reply to Gaunilo - Anselm Canterbury, Erzbischof, Heiliger 1033-1109; Gaunilo Maioris Monasterii; Anselm Canterbury, Erzbischof, Heiliger 1033-1109 (Univ. of Notre Dame Press, 1979)