"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.
Robert H. Schuller (1993). “Robert H Schuller: The Inspirational Writings : Tough Times Never Last, But Tough People Do/Tough Minded Faith for Tender Hearted People”, Bbs Publishing Corporation
L. Frank Baum (2008). “7 Books in 1: L. Frank Baum's "Oz" Series, Volume 1 of 2. the Wonderful Wizard of Oz, the Marvelous Land of Oz, Ozma of Oz, Dorothy”, p.564, Shoes & Ships & Sealing Wax