APA

Herrera M., Pinkley D., . (2010). Backpack Gold. London: Pearson Longman.

Chicago

Herrera Mario, Pinkley Diane, . 2010. Backpack Gold. London: Pearson Longman.

Harvard

Herrera M., Pinkley D., . (2010). Backpack Gold. London: Pearson Longman.

MLA

Herrera Mario, Pinkley Diane, . Backpack Gold. London: Pearson Longman. 2010.