http://royalsociety.metapress.com/openurl.asp?genre=article&id=doi:10.1098/rstb 2004.1598 http://www.journals.royalsoc.ac.uk/app/home/contribution.asp?wasp=d28c01b2496d4 71b788a48bbadfdfbf&referrer=parent&backto=searcharticlesresults,1,1;journal,1,1 homemainpublications,4,7;