Stem Cells Portal, 01 May 2012 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0036121
Stem Cells Portal, 25 Apr 2012 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0036121