Gaya APA

Baumeister, R, F., Tierney, J. (2011). Willpower : Rediscovering the Greatest Human Strength (Ed. 1). USA: Penguin Books.

Gaya MLA

Baumeister, Roy, F.., Tierney, John. "Willpower : Rediscovering the Greatest Human Strength". Ed. 1 USA: Penguin Books, 2011. Text.