Cluster Indexes from Kimberly

http://www.sqlskills.com/blogs/kimberly/more-considerations-for-the-clustering-key-the-clustered-index-debate-continues/

Interesting reading about Indexes in scope of finding the duplicate ones

http://www.sqlskills.com/blogs/kimberly/how-can-you-tell-if-an-index-is-really-a-duplicate