APA (7th ed.) Citation

Obee, B. B., & Evans, V. V. (2004). Key. Workbook Upstream upper Intermediate: Student's book. Express Publishing.

Chicago Style (17th ed.) Citation

Obee, B. Bob, and V. Virginia Evans. Key. Workbook Upstream Upper Intermediate: Student's Book. Newbury: Express Publishing, 2004.

MLA (8th ed.) Citation

Obee, B. Bob, and V. Virginia Evans. Key. Workbook Upstream Upper Intermediate: Student's Book. Express Publishing, 2004.