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.306
Henry St John's letter to Alexander Pope, as quoted in "The Work of Lord Bolingbroke: With a Life, Prepared Expressly for this Edition, Containing Additional Information Relative to His Personal and Public Character, Selected from the Best Authorities. In Four Volumes. Volume III", 1841.
Jean de La Bruyère, Luc de Clapiers marquis de Vauvenargues (1903). “La Bruyère and Vauvenargues: Selections from the Characters, Reflexions and Maxims”