《资治通鉴·唐纪·唐纪七十八》
当时藩镇都被强臣占据，只有嗣薛王李知柔在广州任清海节度使，于是请求让自己代替他。
时籓镇皆为强臣所据，惟嗣薛王知柔在广州，乃求代之。
At that time, the regional military governments were all occupied by powerful officials. Only the heir to the Duke of Xue, Li Zhirou, was the Qinghai military governor of Guangzhou, and so he requested that the emperor replace him.