Collins. (2013). Work on your grammar (Upper Intermediate B2): Over 200 exercises to improve your English grammar. Tổng hợp.
Trích dẫn kiểu ChicagoCollins. Work On Your Grammar (Upper Intermediate B2): Over 200 Exercises to Improve Your English Grammar. Tổng hợp, 2013.
MLA引文Collins. Work On Your Grammar (Upper Intermediate B2): Over 200 Exercises to Improve Your English Grammar. Tổng hợp, 2013.
警告:這些引文格式不一定是100%准確.