By Savage, Alice.. New York, NY, USA : Oxford University Press, 2012 . viii, 152 p. ; 30 cm.. 978-0194323451
]]>By Davis, Jason.. New York : Oxford University Press, 2006 . 184 p. : 28 cm.. 9780194309240 (pbk. : Student bk.) | 019430924X (pbk. : Student bk.) | 9780194308847 (pbk. : Answer key)
]]>By Olsher, David. New York : Oxford University Press, 1996 . viii, 120 p. : 28 cm.. 0194344525 | 0194344592 (teacher's guide)
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