Cita APA (7th ed.)

Obee B. Bob. (2005). Upstream. Upper Intermediate: Workbook: class cas. 1. Newbury, Express Publishing, 2005.

Cita Chicago (17th ed.)

Obee B. Bob. Upstream. Upper Intermediate: Workbook: Class Cas. 1. Newbury, Express Publishing, 2005, 2005.

Cita MLA (9th ed.)

Obee B. Bob. Upstream. Upper Intermediate: Workbook: Class Cas. 1. Newbury, Express Publishing, 2005, 2005.