Dr. David J. Lieberman, Ph.D. (2010). “Get Anyone to Do Anything: Never Feel Powerless Again--With Psychological Secrets to Control and Influence Every Situation”, p.155, Farrar, Straus, and Giroux
Lawrence G. Lovasik (1999). “The Hidden Power of Kindness: A Practical Handbook for Souls who Dare to Transform the World, One Deed at a Time”, p.61, Sophia Institute Press
Nelly Sachs, George Bernard Shaw, Frans Eemil Sillanpää, René Sully-Prudhomme (1971). “Nelly Sachs, Jean-Paul Sartre, George Bernard Shaw, Frans Eemil Sillanpää, René Sully-Prudhomme”