Cita APA (7th ed.)

Langan & John. (2006). English Skills (8th ed.). McGraw-Hill.

Cita Chicago (17th ed.)

Langan i John. English Skills. 8th ed. New York: McGraw-Hill, 2006.

Cita MLA (9th ed.)

Langan i John. English Skills. 8th ed. McGraw-Hill, 2006.