Cita APA (7th ed.)

Kerr, P. (2005). Straightforward: Pre-intermediate. Student's book (1a. ed.). Macmillan Education.

Cita Chicago (17th ed.)

Kerr, Philip. Straightforward: Pre-intermediate. Student's Book. 1a. ed. Oxford: Macmillan Education, 2005.

Cita MLA (9th ed.)

Kerr, Philip. Straightforward: Pre-intermediate. Student's Book. 1a. ed. Macmillan Education, 2005.