APA aipamena

Robinson, B. (1989). Focus: An ESL grammar. New York: St. Martin's Press.

Chicago Style aipamena

Robinson, Barbara. Focus: An ESL Grammar. New York: St. Martin's Press, 1989.

MLA aipamena

Robinson, Barbara. Focus: An ESL Grammar. New York: St. Martin's Press, 1989.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.