Jean M. Twenge and W. Keith Campbell. The Narcissism Epidemic: Living in the Age of Entitlement. Simon and Schuster, 2009, p. 62.

Nathaniel Branden. The Six Pillars of Self-Esteem. Bantam Dell Publishing Group, 1995, p. 5, as cited in Roy F. Baumeister, Laura Smart, and Joseph M. Boden. «Relation of threatened egotism to violence and aggression: The dark side of high self-esteem.» Psychological Review 103.1 (1996): 5.