Marios Mavronicolas Loizos Michael Vicky G. Papadopoulou Anna Philippou Paul G. Spirakis The Price of Defense. 717-728 2006 conf/mfcs/2006 MFCS http://dx.doi.org/10.1007/11821069_62 db/conf/mfcs/mfcs2006.html#MavronicolasMPPS06