This article is interesting, and you can follow the references for further fascinating reading:

http://www.ncbi.nlm.nih.gov/m/pubmed/22109896/#fft.

I have a PDF, but haven't been able to find it online in full. If someone comes across it, please post it in case anyone is interested. I'll see if I can track it down tomorrow.

Edit/Addition: Here we go, a PDF: https://www.google.ca/url?sa=t&rct=j..._BVU0A&cad=rja