Thanks, Hawk The science link came in handy.....R2R....still browsing http://www.sciencedirect.com/science?_ob=ArticleListURL&_method=list&_ArticleListID=1810226173&_sort=r&_st=13&view=c&_acct=C000228598&_version=1&_urlVersion=0&_userid=10&md5=bf80d5c93975ff5bb5cc76e631675dc1&searchtype=a ....you know me,share the joy