Citazione Stile APA (7a Edizione)

Krashen, S. D. (1987). Principles and practice in second language acquisition. Prentice Hall International.

Citazione stile Chigago Style (17a edizione)

Krashen, Stephen D. Principles and Practice in Second Language Acquisition. Nueva York: Prentice Hall International, 1987.

Citatione MLA (9a ed.)

Krashen, Stephen D. Principles and Practice in Second Language Acquisition. Prentice Hall International, 1987.