Graver, B. (1999). Advanced English practice (third edition.). New york: Cambridge University Press.
Chicago Style aipamenaGraver, B.D. Advanced English Practice. third edition. New york: Cambridge University Press, 1999.
MLA aipamenaGraver, B.D. Advanced English Practice. third edition. New york: Cambridge University Press, 1999.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.