Shijie Zhou Zhiguang Qin Feng Zhang Xianfeng Zhang Wei Chen Jinde Liu Colored Petri Net Based Attack Modeling. 715-718 2003 conf/rsfdgrc/2003 RSFDGrC http://dx.doi.org/10.1007/3-540-39205-X_123 db/conf/rsfdgrc/rsfdgrc2003.html#ZhouQZZCL03