Some Thoughts on Teaching Grammar to Improve Writing
http://links.jstor.org/sici?sici=0010-096X%28196702%2918%3A1%3C2%3ASTOTGT%3E2.0.CO%3B2-8
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Baum, Bernard
CCC
1967

Abstract:

The conviction that writing can be improved with a knowledge of grammar has prevailed for quite a long time. But research has shown no correlation between grammatical knowledge and writing ability.