Cita APA (7th ed.)
Nettle, D. (2005). Happiness: The science behind your smile. Oxford University Press.
Cita Chicago (17th ed.)
Nettle, Daniel. Happiness: The Science Behind Your Smile. Oxford, UK ; New York, N.Y.: Oxford University Press, 2005.
Cita MLA (9th ed.)
Nettle, Daniel. Happiness: The Science Behind Your Smile. Oxford University Press, 2005.
Atenció: Aquestes cites poden no estar 100% correctes.