Pubmed website was where i sourced the majority of studies - it's worth looking at as it gives further links to similar studies on the right hand side of the page.
The studies i saved are in the longest internet faves list known to man that are currently unsorted so would take me an evening to wade through, unfortunately i don't have the time at the mo to do this.
I'll make a more comprehensive post with links at some point on this subject as it keeps coming up over and over.