APA aipamena

Obee B. Bob & Evans V. Virginia. (2007). Upstream. Upper-Intermediate B2+: Student's Book. Newbury, Express Publishing, 2007.

Chicago Style aipamena

Obee B. Bob and Evans V. Virginia. Upstream. Upper-Intermediate B2+: Student's Book. Newbury, Express Publishing, 2007, 2007.

MLA aipamena

Obee B. Bob and Evans V. Virginia. Upstream. Upper-Intermediate B2+: Student's Book. Newbury, Express Publishing, 2007, 2007.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.