Citazione Stile APA (7a Edizione)

Obee B. Bob & Evans V. Virginia. (2007). Upstream. Upper-intermediate B2+: Class CD 1. Newbury, Express Publishing, 2007.

Citazione stile Chigago Style (17a edizione)

Obee B. Bob e Evans V. Virginia. Upstream. Upper-intermediate B2+: Class CD 1. Newbury, Express Publishing, 2007, 2007.

Citatione MLA (9a ed.)

Obee B. Bob e Evans V. Virginia. Upstream. Upper-intermediate B2+: Class CD 1. Newbury, Express Publishing, 2007, 2007.