Swan, M., & Walter, C. (1988). The cambridge english course. New York: Cambridge University Press.
Chicago Style aipamenaSwan, Michael, và Catherine Walter. The Cambridge English Course. New York: Cambridge University Press, 1988.
MLA aipamenaSwan, Michael, và Catherine Walter. The Cambridge English Course. New York: Cambridge University Press, 1988.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.