"'Let Us Preach What We Practise': The Fulton Speech and Today's War" by Christopher C. Harmon, The Finest Hourmagazine, 135, p. 25, www.winstonchurchill.org. Summer 2007.
John Muir (1997). “Nature Writings: The Story of My Boyhood and Youth, My First Summer in the Sierra, the Mountains of California, Stickeen, Selected Essays”, p.225, Library of America
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