Biber, D. (1999). Longman grammar of spoken and written English. New York: Longman.
Dyfyniad Arddull ChicagoBiber, Douglas. Longman Grammar of Spoken and Written English. New York: Longman, 1999.
Dyfyniad MLABiber, Douglas. Longman Grammar of Spoken and Written English. New York: Longman, 1999.
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