《新唐书·列传·卷十七》
时逢张道源招抚山东，也派使者劝他归降。武德二年，便奉表以其地归降。
会张道源抚辑山东，亦谕艺降，武德二年，乃奉表以地归。
At that time Zhang Daoyuan was appeasing Shandong, and sent envoys to persuade him to submit. In the second year of the Wude reign, he submitted that territory.