Myrto Arapinis Tom Chothia Eike Ritter Mark Ryan Untraceability in the applied pi-calculus. 1-6 2009 ICITST http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5402514 conf/icitst/2009 db/conf/icitst/icitst2009.html#ArapinisCRR09