University of Illinois
University of Illinois Urbana Champaign: Toefl Practice Site: Coherence and Unity
This site discusses coherence achieved through major and minor connector transitions. Examples are given, and there is a link to an exercise meant for the particular class this site was designed for, still useful practice for anyone....
University of Victoria (Canada)
The U Vic Writer's Guide: Paragraph Unity
This writing lab site presents examples that show students poor unity within a paragraph.