APA (7th ed.) Zitazioa

Ferree, T., & Sanabria, K. (1998). NorthStar: Focus on listening and speaking, high intermediate. Longman.

Chicago Style (17th ed.) Zitazioa

Ferree, Tess, eta Kim Sanabria. NorthStar: Focus on Listening and Speaking, High Intermediate. Nueva York: Longman, 1998.

MLA (9th ed.) Zitazioa

Ferree, Tess, eta Kim Sanabria. NorthStar: Focus on Listening and Speaking, High Intermediate. Longman, 1998.