Short and Simple Sentences
http://www.goodusability.co.uk/2009/01/short-and-simple-sentences/

Hamill, David
Good Usability
2009

Abstract:

When you’re writing for the web, try to keep your sentences under 20 words in length. Your content will be easier to read this way. This is because it’s easier to read a few short sentences than it is to read one big one.