Freeman, David E.
Essential Linguistics / David E.Freeman,
Heinemann, 2004
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Dixson, Robert J.
Essential idioms in English
Regents Publishing, 1981
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Karlsson, Fred
Finnish: an essential grammar
Routledge, 1999
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Donaldson, Bruce
German: an essential grammar
Routledge, 2006
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Lee, Jae-wook
Korean essential vocabulary 6000
Language Plus, 2006
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