Layard, R. (2005). Happiness: Lessons from a new science. Penguin Press.
Lua i Stíl Chicago (17ú heag.)Layard, Richard. Happiness: Lessons from a New Science. New York: Penguin Press, 2005.
Lua MLA (9ú heag.)Layard, Richard. Happiness: Lessons from a New Science. Penguin Press, 2005.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.