APA-viite

Collins. (2013). Work on your grammar (Elementary A1): Over 200 exercises to improve your English grammar. Tổng hợp.

Chicago-tyylinen lähdeviittaus

Collins. Work On Your Grammar (Elementary A1): Over 200 Exercises to Improve Your English Grammar. Tổng hợp, 2013.

MLA-viite

Collins. Work On Your Grammar (Elementary A1): Over 200 Exercises to Improve Your English Grammar. Tổng hợp, 2013.

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