9Y Deswarte, L Blain, J C Fabre. Intrusion tolerance in distributed computing systems [J] In Proc. of the International Symposium on Security and Privacy, Oakland (Ca.), IEEE press, May 20 - 22,1991.110- 121.
10R Sandhu, P Samarati. Access control : principles and practice [J].IEEE Communications, 1994,32(9) :40 - 48.