I like to try and get as close to the source as possible to avoid contamination of the information or whatever.  So I followed his reference here: http://www.ncbi.nlm.nih.gov/pubmed/21587201 Also I found the whole text published on this sweet looking site:  http://www.nature.com/ijo/index.html  It looks to have a lot of info on it but I haven't dug around yet.