《资治通鉴·唐纪·唐纪二十七》
当地有人传说： 、奚、等部落很想归降大唐，只是由于大唐不在柳城设立营州，所以无所依附投靠，再加上被突厥可汗默啜侵扰，故而暂时依附突厥；假如大唐又在柳城设立营州，那么这些部落就会一个接一个地前来归附。 
或言： 靺鞨、奚、大欲降唐，正以唐不建营州，无所依投，为默啜所侵扰，故且附之；若唐复建营州，则相帅归化矣。 
It is rumored locally that the Xi and other tribes are very eager to surrender to the Tang Dynasty, but since the Tang Dynasty did not establish Yingzhou in Liucheng, they have no one to rely on and turn to. In addition, they are harassed by the Turkic Khan Moshu, so they temporarily rely on the Turkic; if the Tang Dynasty establishes Yingzhou in Liucheng again, these tribes will come to surrender one after another. 