Na'aman Kam Irun R. Cohen David Harel The Immune System as a Reactive System: Modeling T Cell Activation With Statecharts. 15-22 2001 conf/vl/2001 HCC http://csdl.computer.org/comp/proceedings/hcc/2001/0474/00/04740015abs.htm db/conf/vl/hcc2001.html#KamCH01