Punctuation Made Simple 

Some people write well but allow themselves to be disabled by a fear of punctuation and grammar. They know how to prewrite, organize, and revise, but proofreading for punctuation and grammar causes them difficulties. There’s no need to fear these conventions of standard written English. In fact, these conventions can help you become a more effective communicator.

Olson, Gary A. Illinois State University (1999). Reference>Style Guides>Editing>Grammar