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.14, Hackett Publishing
Thomas Hobbes (1750). “The Moral and Political Works To which is Prefixed the Autors Life, Extracted from that Said to be Written by Himself ... Illustr. by the Ed. - London 1750”, p.122