APA (7th ed.) Zitazioa
Swan, M. (2016). Practical english usage (4th ed.). Oxford University Press.
Chicago Style (17th ed.) Zitazioa
Swan, Michael. Practical English Usage. 4th ed. United Kingdom: Oxford University Press, 2016.
MLA (9th ed.) Zitazioa
Swan, Michael. Practical English Usage. 4th ed. Oxford University Press, 2016.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.