Gaya APA

Roger, B, Z, D. (2011). Listening Power 1 Language Focus. Comprebension Focus. Listening for Pleasure . United States: United States: Pearson Longman.

Gaya MLA

Roger, Bruce., Zemach,, Dorothy. "Listening Power 1 Language Focus. Comprebension Focus. Listening for Pleasure". United States: United States: Pearson Longman, 2011. Text.