(2001). American headway 1: Workbook. Oxford: Oxford University Press.
Chicago Style aipamenaAmerican Headway 1: Workbook. Oxford: Oxford University Press, 2001.
MLA aipamenaAmerican Headway 1: Workbook. Oxford: Oxford University Press, 2001.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.