Here's an interesting recent paper in the British Medical Journal: "How citation distortions create unfounded authority: analysis of a citation network". (I don't know if this is freely accessible, but the abstract should be.)
From the paper:
"Objective To understand belief in a specific scientific claim by studying the pattern of citations among papers stating it."
"Conclusion Citation is both an impartial scholarly method and a powerful form of social communication. Through distortions in its social use that include bias, amplification, and invention, citation can be used to generate information cascades resulting in unfounded authority of claims. Construction and analysis of a claim specific citation network may clarify the nature of a published belief system and expose distorted methods of social citation."
It also includes a list of specific ways in which citations were found to amplify or invent evidence.