Marian Cox. (2014). Cambridge Checkpoint English Coursebook 9 (Cambridge International Examinations). CAMBRIDGE UNIVERSITY PRESS.
Chicago-viite (17. p.)Marian Cox. Cambridge Checkpoint English Coursebook 9 (Cambridge International Examinations). CAMBRIDGE UNIVERSITY PRESS, 2014.
MLA-viite (9. p.)Marian Cox. Cambridge Checkpoint English Coursebook 9 (Cambridge International Examinations). CAMBRIDGE UNIVERSITY PRESS, 2014.
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