APA

Hill L. A., . (1968). Intermediate refresher course. : Oxford University Press, London.

Chicago

Hill L A, . 1968. Intermediate refresher course. : Oxford University Press, London.

Harvard

Hill L. A., . (1968). Intermediate refresher course. : Oxford University Press, London.

MLA

Hill L A, . Intermediate refresher course. : Oxford University Press, London. 1968.