《资治通鉴·唐纪·唐纪四十二》
杨炎托称北部边防需要大臣镇守抚慰，癸巳，德宗任命京畿观察使崔宁为单于镇北大都护、朔方节度使，镇守坊州。
炎托以北边须大臣镇抚，癸巳，以京畿观察使崔宁为单于、镇北大都护、朔方节度使，镇坊州。
Yang Yan made an excuse that the northern border needed experienced officials to comfort and settle the people, on Guisi Day, Dezong appointed Cui Ning, the Jingji Supervisor, to be the Commander of Shanyu Town, the Protectorate General of the North, and the Military Governor of Shuofang, stationed in Fangzhou.