Gaya APA

Solorzano, H, S., Schmidt, J, P. (2003). NorthStar: Listening and Speaking Intermediate (Ed.2). Inggris: LONGMAN.

Gaya MLA

Solorzano, Helen, S.., Schmidt, Jennifer, P.L. "NorthStar: Listening and Speaking Intermediate". Ed.2 Inggris: LONGMAN, 2003. Text.