(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.