Etherton, A. R. B. (1994). General Certificate English. Nelson.
Chicago Style aipamenaEtherton, A. R. B. General Certificate English. Walton-on-Thames: Nelson, 1994.
MLA aipamenaEtherton, A. R. B. General Certificate English. Nelson, 1994.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.