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
David Hume, Eric Steinberg (1993). “An Enquiry Concerning Human Understanding ; [with] A Letter from a Gentleman to His Friend in Edinburgh ; [and] An Abstract of a Treatise of Human Nature”, p.73, Hackett Publishing
David Hume (1826). “The Philosophical Works: Including All the Essays, and Exhibiting the More Important Alterations and Corrections in the Successive Ed. Publ. by the Author”, p.9