Allen Klein (1989). “The Healing Power of Humor: Techniques for Getting Through Loss, Setbacks, Upsets, Disappointments, Difficulties, Trials, Tribulations, and All that Not-so-funny Stuff”, Tarcher
Henry David Thoreau (2014). “Citizen Thoreau: Walden, Civil Disobedience, Life Without Principle, Slavery in Massachusetts, A Plea for Captain John Brown”, p.152, Graphic Arts Books