《资治通鉴·唐纪·唐纪五十六》
当时，李准备掩袭蔡州，谋划更为隐秘。他单独叫来李和李忠义，屏退外人后才进行交谈，有时谈话一直延续到夜半，别人都不能够参与商议。
时愬欲袭蔡，而更密其谋，独召祐及李忠义屏人语，或至夜分，他人莫得预闻。
At that time, Li was preparing to ambush Caizhou, and his plan was even more secretive. He called Li and Li Zhongyi alone, and talked after dismissing outsiders. Sometimes he talked until midnight, and no one else could participate in the discussion.