John George Nicolay (2008). “A Short Life of Abraham Lincoln: Condensed from Nicolay & Hay's Abraham Lincoln: a History: Easyread Large Edition”, p.24, ReadHowYouWant.com
Henry David Thoreau (2014). “Citizen Thoreau: Walden, Civil Disobedience, Life Without Principle, Slavery in Massachusetts, A Plea for Captain John Brown”, p.28, Graphic Arts Books