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
Frances Wright (1829). “Course of popular lectures; with 3 addresses on various public occasions, and a reply to the charges against the French reformers of 1789”, p.45