एपीए उद्धरण

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

शिकागो स्टाइल उद्धरण

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

एमएलए उद्धरण

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