APA

Widdowson H., . (1990). Aspects of language teaching. : Oxford university press.

Chicago

Widdowson H.G, . 1990. Aspects of language teaching. : Oxford university press.

Harvard

Widdowson H., . (1990). Aspects of language teaching. : Oxford university press.

MLA

Widdowson H.G, . Aspects of language teaching. : Oxford university press. 1990.