Cita APA (7a ed.)

Langan, J. (2006). English skills (5th ed.). McGraw-Hill.

Cita Chicago Style (17a ed.)

Langan, John. English Skills. 5th ed. New York: McGraw-Hill, 2006.

Cita MLA (9a ed.)

Langan, John. English Skills. 5th ed. McGraw-Hill, 2006.