Cita APA (7th ed.)

LANGAN, J. (1977). English skills. McGraw-Hill.

Cita Chicago (17th ed.)

LANGAN, John. English Skills. New York: McGraw-Hill, 1977.

Cita MLA (9th ed.)

LANGAN, John. English Skills. McGraw-Hill, 1977.

Atenció: Aquestes cites poden no estar 100% correctes.