《旧唐书·本纪·卷十一》
六月一日，以太子詹事臧希让任检校工部尚书，充任渭北节度使；以渭北节度使李光进为太子太保。
六月丁酉，以太子詹事臧希让检校工部尚书，充渭北节度；以渭北节度李光进为太子太保。
On the 1st day of June, Zang Xirang, Prince's Tutor, was appointed as Inspector and Imperial Minister of the Ministry of Industry and concurrently as Overseer of the Circuit for Northern Weishui; Li Guangjin, Overseer of the Circuit for Northern Weishui, was appointed as Grand Protector for the Crown Prince.