Gerhard Popp Jan Jürjens Guido Wimmel Ruth Breu Security-Critical System Development with Extended Use Cases. 478-487 2003 conf/apsec/2003 APSEC http://csdl.computer.org/comp/proceedings/apsec/2003/2011/00/20110478abs.htm db/conf/apsec/apsec2003.html#PoppJWB03