Gaya APA

Harris, Michael, Mower, David, Sikorzynska, Anna. (2007). Challenges Student's Book 4 (Cet 1). New York: Pearson Longman.

Gaya Chicago

Harris, Michael, Mower, David, Sikorzynska, Anna. Challenges Student's Book 4. Cet 1 New York: Pearson Longman, 2007. Text.

Gaya MLA

Harris, Michael, Mower, David, Sikorzynska, Anna. Challenges Student's Book 4. Cet 1 New York: Pearson Longman, 2007. Text.

Gaya Turabian

Harris, Michael, Mower, David, Sikorzynska, Anna. Challenges Student's Book 4. Cet 1 New York: Pearson Longman, 2007. Print.