Barka E,Sandhu R S.A Role-Based Delegation Model and Some Extensions.In Proceeding of 23rd National Information Systems Security Conference.是什么意思_Barka E,Sandhu R S.A Role-Based Delegation Model and Some Extensions.In Proceeding of 23rd National Information Systems Security Conference.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句