George R. R. Martin (2012). “George R. R. Martin's A Game of Thrones 5-Book Boxed Set (Song of Ice and Fire Series): A Game of Thrones, A Clash of Kings, A Storm of Swords, A Feast for Crows, and and A Dance with Dragons”, p.1307, Bantam
Wallace D. Wattles (2015). “The Science of Being Great: Personal Self-Help Book of Wallace D. Wattles (Unabridged): From one of The New Thought pioneers, author of The Science of Getting Rich, The Science of Being Well, How to Get What You Want, Hellfire Harrison, How to Promote Yourself and A New Christ”, p.5, e-artnow
Abraham Lincoln, Don Edward Fehrenbacher (1977). “Abraham Lincoln, a Documentary Portrait Through His Speeches and Writings”, p.39, Stanford University Press
Thomas Jefferson (1854). “The writings of Thomas Jefferson: being his autobiography, correspondence, reports, messages, addresses, and other writings, official and private”, p.257
Thomas Jefferson (1884). “The Works of Thomas Jefferson: Published by Order of Congress from the Original Manuscripts Deposited in the Department of State”
Thomas Jefferson (1854). “The writings of Thomas Jefferson: being his autobiography, correspondence, reports, messages, addresses, and other writings, official and private”, p.152