Eugene O'Neill (1988). “Complete Plays: 1920-1931”, New York, N.Y. : Literary Classics of the United States : Distributed to the trade in the U.S. and Canada by the Viking Press
Wayne W. Dyer (2009). “The Invisible Force: 365 Ways to Apply the Power of Intention to Your Life: Easyread Super Large 18pt Edition”, p.106, ReadHowYouWant.com