APA (7th ed.) Citation

Duff, A. (1981). The third language. Pergamon Press, Ltd.

Chicago Style (17th ed.) Citation

Duff, Alan. The Third Language. Oxford: Pergamon Press, Ltd, 1981.

MLA (9th ed.) Citation

Duff, Alan. The Third Language. Pergamon Press, Ltd, 1981.

Warning: These citations may not always be 100% accurate.