Cita APA (7th ed.)
Langan, J. (1981). English Skills (2nd ed.). McGraw-Hill.
Cita Chicago (17th ed.)
Langan, John. English Skills. 2nd ed. New York: McGraw-Hill, 1981.
Cita MLA (9th ed.)
Langan, John. English Skills. 2nd ed. McGraw-Hill, 1981.
Atenció: Aquestes cites poden no estar 100% correctes.