Cita APA (7th ed.)

Singleton, D., & Lengyel, Z. (1995). The age factor in second language acquisition: A critical look at the critical period hypothesis. Muktilingual Matters LTD.

Cita Chicago (17th ed.)

Singleton, David, i Zsolt Lengyel. The Age Factor in Second Language Acquisition: A Critical Look at the Critical Period Hypothesis. Clevedon: Muktilingual Matters LTD, 1995.

Cita MLA (9th ed.)

Singleton, David, i Zsolt Lengyel. The Age Factor in Second Language Acquisition: A Critical Look at the Critical Period Hypothesis. Muktilingual Matters LTD, 1995.