David Hume, Eric Steinberg (1992). “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.10, Hackett Publishing
David Hume, Thom Chittom (2004). “An Enquiry Concerning Human Understanding: And Selections from a Treatise of Human Nature”, p.200, Barnes & Noble Publishing
David Hume (1824). “The Philosophical Works of David Hume ... Containing Dialogues Concerning Natural Religion, Essays on the Immortality of the Soul, Suicide ... &c. A New Edition”, p.24