Theodore Roosevelt (2015). “Theodore Roosevelt on Bravery: Lessons from the Most Courageous Leader of the Twentieth Century”, p.19, Skyhorse Publishing, Inc.
"John Legend: 'I thought it would be funny to take a photo in the White House bathroom'". Interview with Denise Cheong and Charlene Fang, travel.cnn.com. March 9, 2011.
Orison Swett Marden (2015). “ORISON SWETT MARDEN Premium Collection - Wisdom & Empowerment Series (18 Books in One Volume): Steps to Success and Power, How to Get What You Want, An Iron Will, Be Good to Yourself, Every Man A King, Keeping Fit, Prosperity – How to Attract It, Stepping-Stones To Fame And Fortune...”, p.51, e-artnow