《资治通鉴·唐纪·唐纪六十三》
李德裕上奏说： 黠戛斯已经自称可汗，现在，朝廷要想借助他的兵力消灭回鹘残余，恐怕不应当吝惜一个可汗的名号。
德裕奏： 黠戛斯已自称可汗，今欲藉其力，恐不可吝此名。
Li Deyu submitted that, since Xiajiasi had already proclaimed himself Kehan, the court should not spare the title to ask for his help to deal with the Uyghur remnants.