"The 100 best nonfiction books: No 68 - Narrative of the Life of Frederick Douglass, an American Slave by Frederick Douglass (1845)" by Robert McCrum, www.theguardian.com. May 22, 2017.
Lawrence G. Lovasik (1999). “The Hidden Power of Kindness: A Practical Handbook for Souls who Dare to Transform the World, One Deed at a Time”, p.85, Sophia Institute Press
Booker T. Washington (1904*). “Address of Booker T. Washington, Principal of the Tuskegee Normal & Industrial Institute: Before the National Educational Association, St. Louis, Missouri, June 30, 1904”