APA stil citiranja

Willis, R. (1970). Helping verbs: Helping verbs (2nd impression.). London: Longman.

Chicago stil citiranja

Willis, Roger. Helping verbs: Helping verbs. 2nd impression. London: Longman, 1970.

MLA stil citiranja

Willis, Roger. Helping verbs: Helping verbs. 2nd impression. London: Longman, 1970.

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