Dyfyniad APA

Layard, R. (2005). Happiness: Lessons from a new science. Penguin Press.

Dyfyniad Arddull Chicago

Layard, Richard. Happiness: Lessons from a New Science. New York: Penguin Press, 2005.

Dyfyniad MLA

Layard, Richard. Happiness: Lessons from a New Science. Penguin Press, 2005.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.