Valentinus on Exodus 33,20: Valentinian traditions in the "Gospel of Truth" and in Origen's "Commentary on John" - MacCree, John W. (Perrone, Lorenzo 1946- (edt), Origen and the Alexandrian tradition: Papers of the 8th International Origen Congress, Pisa, 27 - 31 August 2001 = Origene e la tradizione alessandrina, 2003)