Layard, R. (2005). Happiness: Lessons from a new science. Penguin Press.
Chicago Style (17. basım) AtıfLayard, Richard. Happiness: Lessons from a New Science. New York: Penguin Press, 2005.
MLA (9th ed.) AtıfLayard, Richard. Happiness: Lessons from a New Science. Penguin Press, 2005.
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