David Hume (1874). “A Treatise on Human Nature: Being an Attempt to Introduce the Experimental Method of Reasoning Into Moral Subjects; and Dialogues Concerning Natural Religion”, p.245
Jean de La Bruyère, Luc de Clapiers marquis de Vauvenargues (1903). “La Bruyère and Vauvenargues: Selections from the Characters, Reflexions and Maxims”
"'The Economy Fell off the Cliff'". Interview with Mathias Müller von Blumencron, Gregor Peter Schmitz and Gabor Steingart, www.spiegel.de. November 24, 2008.