APA Style

Ferre, T., Sanabria, K. (2015). NorthStar 4 : Listening & Speaking (Fourth edition) . New York: Pearson Education.

MLA Style

Ferre, Tess., Sanabria, Kim. "NorthStar 4 : Listening & Speaking (Fourth edition)". New York: Pearson Education, 2015. Buku SMA Athalia.