Joseph Bancroft, Robert Barclay (1874). “A Persuasive to Unity: Setting Forth the Ground of that Source of Comfort in which Ground of a Clean Heart and a Right Spirit Men May Grow in Good and Firmly Support Each Other as Living Stones in the Temple of God”, p.124
"La Philosophie comme manière de vivre: Entretiens avec Jeannie Carlier et Arnold I. Davidson" by Pierre Hadot, Jeannie Carlier, Arnold I. Davidson, Paris: Albin Michel, translated by Michael Chase, (p. 264), 2001.