Gaya APA

Herrera, Mario. (2009). Backpack 2. Second Edition . USA: Pearson Longman.

Gaya Chicago

Herrera, Mario. Backpack 2. Second Edition. USA: Pearson Longman, 2009. Text.

Gaya MLA

Herrera, Mario. Backpack 2. Second Edition. USA: Pearson Longman, 2009. Text.

Gaya Turabian

Herrera, Mario. Backpack 2. Second Edition. USA: Pearson Longman, 2009. Print.