Robert Louis Stevenson (2015). “Collected Memoirs, Travel Sketches and Island Literature of Robert Louis Stevenson: Autobiographical Writings and Essays by the prolific Scottish novelist, poet and travel writer, author of Treasure Island, The Strange Case of Dr. Jekyll and Mr. Hyde, Kidnapped & Catriona”, p.452, e-artnow
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.533, e-artnow
Robert Collier (2013). “The Secret of the Ages: The Secret Edition - Open Your Heart to the Real Power and Magic of Living Faith and Let the Heaven Be in You, Go Deep Inside Yourself and Back, Feel the Crazy and Divine Love and Live for Your Dreams”, p.99, Lulu Press, Inc