Howard Barringer Dov M. Gabbay John Woods Temporal Dynamics of Support and Attack Networks: From Argumentation to Zoology. 59-98 2005 conf/birthday/2005siekmann Mechanizing Mathematical Reasoning http://springerlink.metapress.com/openurl.asp?genre=article&id=MC7ARA6L0JGJNAVE db/conf/birthday/siekmann2005.html#BarringerGW05