Cita APA (7th ed.)

Singleton, D., & Ryan, L. (2004). Language acquisition: The age factor (2nd ed.). Multilingual Matters Ltd..

Cita Chicago (17th ed.)

Singleton, David, i Lisa Ryan. Language Acquisition: The Age Factor. 2nd ed. Clevedon: Multilingual Matters Ltd., 2004.

Cita MLA (9th ed.)

Singleton, David, i Lisa Ryan. Language Acquisition: The Age Factor. 2nd ed. Multilingual Matters Ltd., 2004.