Thomas Hobbes, Alan Cromartie, Quentin Skinner (2005). “Thomas Hobbes: Writings on Common Law and Hereditary Right: A Dialogue Between a Philosopher and a Student, of the Common Laws of England. Questions Relative to Hereditary Right”, p.10, Oxford University Press
William Penn (1807). “Fruits of solitude in reflections and maxims relating to the conduct of human life: Also, his advice to his children relating to their civil and religious conduct, to which are added extracts from the writings of William Law & Judge Hale; with a "Description of the happy man & true gentleman."”, p.28
Charles Babbage (1830). “Reflections on the Decline of Science in England: And on Some of Its Causes, by Charles Babbage (1830). To which is Added On the Alleged Decline of Science in England, by a Foreigner (Gerard Moll) with a Foreword by Michael Faraday (1831).”, p.5