Gaya APA

Kristen, S, ,., Beuckens, T. (2010). Impact conversation 1 (Cet.2). Hongkong: Pearson education Asia.

Gaya MLA

Kristen, Sullivan, ,., Beuckens, Todd. "Impact conversation 1". Cet.2 Hongkong: Pearson education Asia, 2010. Umum.