APA (7th ed.) Citation

Singleton, D. M. (1989). Language acquisition: The age factor. Multilingual Matters.

Chicago Style (17th ed.) Citation

Singleton, D. M. Language Acquisition: The Age Factor. Clevedon, Avon, England ; Philadelphia, Pa, USA: Multilingual Matters, 1989.

MLA (9th ed.) Citation

Singleton, D. M. Language Acquisition: The Age Factor. Multilingual Matters, 1989.