Charles Darwin (1861). “On the Origin of Species by Means of Natural Selection; Or, The Preservation of Favoured Races in the Struggle for Life”, p.358
John Milton, James Prendeville (1850). “Milton's Paradise Lost: With Copious Notes, Explanatory and Critical, Partly Selected from Addison, Bentley, Bowle ... [et Al.] and Partly Original”, p.246