APA-referens (7:e uppl.)

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

Chicago-referens (17:e uppl.)

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

MLA-referens (9:e uppl.)

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