APA aipamena

Praag, B. M. S. v. Happiness quantified. Oxford University Press.

Chicago Style aipamena

Praag, Bernard M. S. van. Happiness Quantified. Oxford University Press.

MLA aipamena

Praag, Bernard M. S. van. Happiness Quantified. Oxford University Press.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.